Geography of Mauritania#Extreme points

The climate is characterized by extremes in temperature and by meager and irregular rainfall. Annual temperature variations are small, although diurnal variations can be extreme. The harmattan, a hot, dry, and often dust-laden wind, blows from the Sahara throughout the long dry season and is the prevailing wind, except along the narrow coastal strip, which is influenced by oceanic trade winds. Most rain falls during the short rainy season (hivernage), from July to September, and average annual precipitation varies from {{convert|500|to|600|mm|in|1}} in the far south to less than {{convert|100|mm|in|1}} in the northern two-thirds of the country.

Image:ASTER Richat.jpg structure. With a diameter of almost {{convert|50|km|mi|0|sp=us}}, it has become a landmark for Space Shuttle crews. Initially interpreted as a meteorite impact structure because of its high degree of circularity, it is now thought to be merely a symmetrical uplift (circular anticline) that has been laid bare by erosion. Paleozoic quartzites form the resistant beds outlining the structure.]]

Mauritania has four ecological zones: the Saharan Zone, the Sahelian Zone, the Senegal River Valley, and the Coastal Zone. Although the zones are markedly different from one another, no natural features clearly delineate the boundaries between them. Sand, varying in color and composition, covers 40 percent of the surface of the country, forming dunes that appear in all zones except the Senegal River Valley. Fixed sand dunes are composed of coarse, fawn-colored sand, while shifting ("mobile") dunes consist of fine, dustlike, reddish-colored sands that can be carried by the wind. Plateaus generally are covered with heavier blue, gray, and black sands that form a crusty surface over layers of soft, loose sand.

Image:Dust Plume off Mauritania.jpg plume off Mauritania.]]

The Saharan Zone makes up the northern two-thirds of the country. Its southern boundary corresponds to the isohyet (a line on the Earth's surface along which the rainfall is the same) that represents annual precipitation of {{convert|150|mm|in|1}}. Rain usually falls during the hivernage, which lasts from July to September. Often, isolated storms drop large amounts of water in short periods of time. A year, or even several years, may pass without any rain in some locations.

Diurnal variations in temperature in the Saharan Zone may be extreme, although annual variations are minimal. During December and January, temperatures range from an early morning low of {{convert|0|°C}} to a midafternoon high of {{convert|38|°C|1}}. During May, June, and July, temperatures range from {{convert|16|°C|1}} in the morning to more than {{convert|49|°C|1}} by afternoon. Throughout the year, the harmattan often causes blinding sandstorms.

The administrative regions (formerly called cercles) of Tiris Zemmour in the north, Adrar in the center, and northern Hodh ech Chargui in the east, which make up most of the Saharan Zone, are vast empty stretches of dunes alternating with granite outcroppings. After a rain, or in the presence of a well, these outcroppings may support vegetation. In the populated Adrar and Tagant plateaus, springs and wells provide water for pasturage and some agriculture. In the western portion of the Saharan Zone, extending toward Nouakchott, rows of sand dunes are aligned from northeast to southwest in ridges from two to twenty kilometres wide. Between these ridges are depressions filled with limestone and clayey sand capable of supporting vegetation after a rain. Dunes in the far north shift with the wind more than those in the south.

The Saharan Zone has little vegetation. Some mountainous areas with a water source support small-leafed and spiny plants and scrub grasses suitable for camels. Because seeds of desert plants can remain dormant for many years, dunes often sprout sparse vegetation after a rain. In depressions between dunes, where the water is nearer the surface, some flora—including acacias, soapberry trees, capers, and swallowwort—may be found. Saline areas have a particular kind of vegetation, mainly chenopods, which are adapted to high salt concentrations in the soil. Cultivation is limited to oases, where date palms are used to shade other crops from the sun.

{{Weather box

|width = auto

|location = Zouerat

|metric first = yes

|single line = yes

|Jan record high C = 34

|Feb record high C = 34

|Mar record high C = 37

|Apr record high C = 40

|May record high C = 43

|Jun record high C = 46

|Jul record high C = 47

|Aug record high C = 46

|Sep record high C = 44

|Oct record high C = 41

|Nov record high C = 38

|Dec record high C = 36

|year record high C = 47

|Jan high C = 22

|Feb high C = 25

|Mar high C = 26

|Apr high C = 31

|May high C = 33

|Jun high C = 36

|Jul high C = 40

|Aug high C = 40

|Sep high C = 37

|Oct high C = 32

|Nov high C = 27

|Dec high C = 23

|year high C = 31

|Jan low C = 12

|Feb low C = 15

|Mar low C = 16

|Apr low C = 18

|May low C = 20

|Jun low C = 23

|Jul low C = 26

|Aug low C = 27

|Sep low C = 26

|Oct low C = 22

|Nov low C = 18

|Dec low C = 14

|year low C = 20

|Jan record low C = 6

|Feb record low C = 8

|Mar record low C = 10

|Apr record low C = 10

|May record low C = 12

|Jun record low C = 15

|Jul record low C = 16

|Aug record low C = 18

|Sep record low C = 17

|Oct record low C = 12

|Nov record low C = 10

|Dec record low C = 6

|year record low C = 6

|Jan precipitation mm = 4

|Feb precipitation mm = 2

|Mar precipitation mm = 2

|Apr precipitation mm = 1

|May precipitation mm = 1

|Jun precipitation mm = 2

|Jul precipitation mm = 3

|Aug precipitation mm = 8

|Sep precipitation mm = 21

|Oct precipitation mm = 5

|Nov precipitation mm = 4

|Dec precipitation mm = 3

|source 1 = Weatherbase

}}

{{Weather box

|width = auto

|metric first=yes

|single line=yes

|location=Atar

|Jan high C=28.0

|Feb high C=31.0

|Mar high C=33.0

|Apr high C=36.0

|May high C=40.0

|Jun high C=43.0

|Jul high C=44.0

|Aug high C=44.0

|Sep high C=42.0

|Oct high C=38.0

|Nov high C=33.0

|Dec high C=29.0

|Jan mean C = 21.0

|Feb mean C = 24.0

|Mar mean C = 26.5

|Apr mean C = 29.5

|May mean C = 33.0

|Jun mean C = 35.5

|Jul mean C = 36.5

|Aug mean C = 36.5

|Sep mean C = 35.0

|Oct mean C = 32.0

|Nov mean C = 27.0

|Dec mean C = 22.5

|Jan low C=14.0

|Feb low C=17.0

|Mar low C=20.0

|Apr low C=23.0

|May low C=26.0

|Jun low C=28.0

|Jul low C=29.0

|Aug low C=29.0

|Sep low C=28.0

|Oct low C=26.0

|Nov low C=21.0

|Dec low C=16.0

|Jan precipitation mm=1

|Feb precipitation mm=1

|Mar precipitation mm=1

|Apr precipitation mm=0

|May precipitation mm=1

|Jun precipitation mm=1

|Jul precipitation mm=2

|Aug precipitation mm=11

|Sep precipitation mm=11

|Oct precipitation mm=3

|Nov precipitation mm=0

|Dec precipitation mm=1

|Jan rain days=0.3

|Feb rain days=0.2

|Mar rain days=0.1

|Apr rain days=0.1

|May rain days=0.2

|Jun rain days=0.4

|Jul rain days=1.1

|Aug rain days=2.3

|Sep rain days=2.0

|Oct rain days=0.6

|Nov rain days=0.3

|Dec rain days=0.2

|Jan sun=276.0

|Feb sun=264.0

|Mar sun=322.0

|Apr sun=325.0

|May sun=341.0

|Jun sun=325.0

|Jul sun=317.0

|Aug sun=303.0

|Sep sun=264.0

|Oct sun=265.0

|Nov sun=273.0

|Dec sun=267.0

|source 1= Climate Atar - meteoblue{{Cite web |url=https://www.meteoblue.com/en/weather/forecast/modelclimate/atar_mauritania_2381334 |title=Climate Atar |access-date=2014-01-15 }}

|source 2= Étude méthodologique pour l'utilisation des données climatologiques de l'Afrique tropicale (French document for sunshine hours only) {{cite web|title=Étude méthodologique pour l'utilisation des données climatologiques de l'Afrique tropicale|url=http://horizon.documentation.ird.fr/exl-doc/pleins_textes/divers12-12/20178.pdf|website=horizon.documentation.ird.fr/|publisher=Comité interafricain d'études hydrauliques|access-date=3 December 2015}}

}}

The Sahelian Zone extends south of the Saharan Zone to within approximately 30 kilometres of the Senegal River. It forms an east–west belt with its axis running from Boutilimit through 'Ayoûn el 'Atroûs to Néma, including the Aoukar basin. The area is mostly made up of steppes and savanna grasslands. Herds of cattle, sheep, and goats move across this zone in search of pasturage.

The hivernage begins earlier in the Sahelian Zone than in the Saharan Zone, often lasting from June until October. Because farmers and herders depend on annual rains, a delay of one month in the beginning of the rainy season can cause large losses and lead to mass migrations from Hodh ech Chargui and Hodh el Gharbi into Mali. Although temperature extremes are narrower than in the Saharan Zone, daily variations range from {{convert|16|to|21|°C|°F|1}}. The harmattan is the prevailing wind.

In the northern Sahel, dunes are covered with scrub grasses and spiny acacia trees. Farther south, greater rainfall permits denser vegetation. Sands begin to give way to clay. Large date palm plantations are found on the Tagant Plateau, and savanna grasses, brushwood, balsam, and spurge cover fixed dunes. Occasional baobab trees dot the flat savanna grasslands of the southern Sahel. Forest areas contain palm trees and baobabs. Vast forests of gum-bearing acacia grow in Trarza and Brakna regions. Farther south, particularly in Assaba and the northern portion of Guidimaka regions, rainfall is high enough to support forms of sedentary agriculture.

{{Weather box

|width = auto

|location = Néma (altitude {{convert|269|m|ft|0|disp=or}})

| metric first = yes

| single line = yes

| Jan high C = 30.0

| Feb high C = 33.0

| Mar high C = 37.0

| Apr high C = 40.0

| May high C = 42.0

| Jun high C = 42.0

| Jul high C = 38.0

| Aug high C = 35.0

| Sep high C = 37.0

| Oct high C = 39.0

| Nov high C = 36.0

| Dec high C = 31.0

| year high C = 36.7

| Jan mean C = 23.0

| Feb mean C = 26.2

| Mar mean C = 30.4

| Apr mean C = 33.3

| May mean C = 37.0

| Jun mean C = 35.8

| Jul mean C = 33.4

| Aug mean C = 31.8

| Sep mean C = 32.3

| Oct mean C = 33.7

| Nov mean C = 29.2

| Dec mean C = 23.5

| year mean C = 30.7

| Jan low C = 17.0

| Feb low C = 19.0

| Mar low C = 23.0

| Apr low C = 26.0

| May low C = 29.0

| Jun low C = 28.0

| Jul low C = 26.0

| Aug low C = 24.0

| Sep low C = 25.0

| Oct low C = 26.0

| Nov low C = 23.0

| Dec low C = 18.0

| year low C = 23.7

| rain colour = green

| Jan rain mm = 1

| Feb rain mm = 1

| Mar rain mm = 1

| Apr rain mm = 4

| May rain mm = 9

| Jun rain mm = 27

| Jul rain mm = 62

| Aug rain mm = 105

| Sep rain mm = 55

| Oct rain mm = 12

| Nov rain mm = 1

| Dec rain mm = 1

| Jan humidity = 18

| Feb humidity = 16

| Mar humidity = 14

| Apr humidity = 14

| May humidity = 22

| Jun humidity = 39

| Jul humidity = 58

| Aug humidity = 68

| Sep humidity = 59

| Oct humidity = 30

| Nov humidity = 20

| Dec humidity = 22

| year humidity = 32

| source 1 = Arab Meteorology Book{{cite web|url=http://extras.springer.com/2007/978-1-4020-4577-6/Book_Shahin_ISBN_9781402045776_Appendix.pdf|title=Meteorological Data|date=March 2016|access-date=20 March 2016|archive-date=4 March 2016|archive-url=https://web.archive.org/web/20160304072830/http://extras.springer.com/2007/978-1-4020-4577-6/Book_Shahin_ISBN_9781402045776_Appendix.pdf|url-status=dead}}}}

{{Weather box

|width = auto

|location = Kiffa, Mauritania

|single line = Y

|metric first= Y

|Jan record high C=40

|Feb record high C=46

|Mar record high C=45

|Apr record high C=46

|May record high C=47

|Jun record high C=48

|Jul record high C=46

|Aug record high C=44

|Sep record high C=43

|Oct record high C=42

|Nov record high C=41

|Dec record high C=38

|year record high C=48

| Jan high C = 28

| Feb high C = 32

| Mar high C = 35

| Apr high C = 39

| May high C = 41

| Jun high C = 41

| Jul high C = 37

| Aug high C = 36

| Sep high C = 36

| Oct high C = 37

| Nov high C = 34

| Dec high C = 30

|year high C = 36

|Jan mean C=23

|Feb mean C=26

|Mar mean C=28

|Apr mean C=32

|May mean C=35

|Jun mean C=36

|Jul mean C=33

|Aug mean C=32

|Sep mean C=32

|Oct mean C=32

|Nov mean C=28

|Dec mean C=23

|year mean C=30

|Jan record low C=5

|Feb record low C=11

|Mar record low C=8

|Apr record low C=11

|May record low C=12

|Jun record low C=19

|Jul record low C=21

|Aug record low C=20

|Sep record low C=21

|Oct record low C=16

|Nov record low C=10

|Dec record low C=2

|year record low C=2

| Jan low C = 17

| Feb low C = 18

| Mar low C = 22

| Apr low C = 26

| May low C = 29

| Jun low C = 30

| Jul low C = 28

| Aug low C = 27

| Sep low C = 27

| Oct low C = 26

| Nov low C = 21

| Dec low C = 17

|year low C = 24

| Jan rain mm = 1

| Feb rain mm = 1

| Mar rain mm = 0

| Apr rain mm = 0

| May rain mm = 2

| Jun rain mm = 22

| Jul rain mm = 72

| Aug rain mm = 120

| Sep rain mm = 73

| Oct rain mm = 15

| Nov rain mm = 2

| Dec rain mm = 2

|Jan rain days=1

|Feb rain days=1

|Mar rain days=0

|Apr rain days=0

|May rain days=1

|Jun rain days=1

|Jul rain days=2

|Aug rain days=3

|Sep rain days=2

|Oct rain days=1

|Nov rain days=1

|Dec rain days=1

|year rain days=13

|rain colour = green

|source 1 = [http://www.weatherbase.com/weather/weather.php3?s=89416&cityname=Kifa-Mauritania Weatherbase]

}}

The Senegal River Valley, sometimes known as the Chemama or the pre-Sahel, is a narrow belt of land that extends north of the Senegal River. Before the droughts of the 1960s, 1970s, and 1980s, the belt ranged from {{convert|16|to|30|km|mi|0}} north of the river. By the late 1980s, desertification had reached the northern bank of the river in some parts of the valley. The valley is wider in Guidimaka Region and is completely dominated by the seasonal cycle of the river. Almost all of the valley's economically active population engages in sedentary agriculture or fishing along the Senegal River and its main tributaries—the Karakoro, the Gorgol, and the Garfa. This area supplies most of the country's agricultural production.

The climate of the Senegal River Valley contrasts with that of the Saharan and Sahelian zones. Rainfall is higher than in other regions, ranging from {{convert|400|to|600|mm|in|1}} annually, usually between May and September. This rainfall, combined with annual flooding of the river, provides the basis for agriculture. Temperatures are cooler and subject to less annual and diurnal variation than in other regions.

The Senegal is the only permanent river between southern Morocco and central Senegal. From its source in Guinea, it flows north and west {{convert|2500|km|mi|0}}, reaching the Atlantic Ocean at Saint Louis, Senegal. From its mouth, the river is navigable as far as Kayes, Mali, during the rainy season and Podor, Senegal, during the rest of the year. Heavy rains, beginning in April in Guinea and May and June in Senegal and Mali, bring annual floods. These floods cover the entire valley up to a width of {{convert|25|to|35|km|mi|0}}, filling numerous lakes and sloughs (marigots) that empty back into the river during the dry season. A notable example of these is Lake R'Kiz. When the waters recede from the bottomlands, planting begins.

The Senegal River Valley, with its rich alluvial and clayey soil, is comparatively abundant in flora. Moreover, higher rainfall, irrigation, and abundant side channels and sloughs tend to produce a lush, near-tropical vegetation, with baobab and gonakie trees and abundant rich grasses. Ddounm and barussus palms are also found here. Much of the flood plain is cultivated.

{{Weather box

|collapsed=

|open=

|metric first=yes

|single line= yes

|location= Rosso

|Jan record high C=37

|Feb record high C=42

|Mar record high C=43

|Apr record high C=45

|May record high C=45

|Jun record high C=45

|Jul record high C=45

|Aug record high C=43

|Sep record high C=42

|Oct record high C=45

|Nov record high C=42

|Dec record high C=40

|year record high C=45

|Jan high C=29

|Feb high C=32

|Mar high C=33

|Apr high C=36

|May high C=37

|Jun high C=36

|Jul high C=34

|Aug high C=34

|Sep high C=35

|Oct high C=36

|Nov high C=33

|Dec high C=30

|year high C=34

|Jan mean C=23

|Feb mean C=26

|Mar mean C=27

|Apr mean C=28

|May mean C=30

|Jun mean C=31

|Jul mean C=30

|Aug mean C=30

|Sep mean C=30

|Oct mean C=31

|Nov mean C=25

|Dec mean C=25

|year mean C=28

|Jan low C=17

|Feb low C=19

|Mar low C=20

|Apr low C=21

|May low C=23

|Jun low C=25

|Jul low C=25

|Aug low C=26

|Sep low C=26

|Oct low C=25

|Nov low C=22

|Dec low C=18

|year low C=22

|Jan record low C=8

|Feb record low C=11

|Mar record low C=11

|Apr record low C=11

|May record low C=12

|Jun record low C=13

|Jul record low C=20

|Aug record low C=22

|Sep record low C=19

|Oct record low C=16

|Nov record low C=11

|Dec record low C=7

|year record low C=7

|unit precipitation days=

|precip days colour=

|Jan precipitation days=1

|Feb precipitation days=1

|Mar precipitation days=0

|Apr precipitation days=0

|May precipitation days=0

|Jun precipitation days=0

|Jul precipitation days=2

|Aug precipitation days=4

|Sep precipitation days=3

|Oct precipitation days=1

|Nov precipitation days=0

|Dec precipitation days=1

|year precipitation days=13

|source 1= Weatherbase{{Cite web |url=http://www.weatherbase.com/weather/weatherall.php3?s=98416&units= |title=Rosso, Mauritania|publisher=Weatherbase |access-date=August 16, 2014 }}

}}

{{Weather box|location = Boghe

|metric first = Y

|single line = Y

|Jan high C = 31.4

|Feb high C = 33.6

|Mar high C = 36.3

|Apr high C = 39.0

|May high C = 40.7

|Jun high C = 40.8

|Jul high C = 38.2

|Aug high C = 36.5

|Sep high C = 37.3

|Oct high C = 38.3

|Nov high C = 36.0

|Dec high C = 31.3

|Jan low C = 14.5

|Feb low C = 16.2

|Mar low C = 19.6

|Apr low C = 21.6

|May low C = 24.1

|Jun low C = 25.4

|Jul low C = 25.7

|Aug low C = 25.9

|Sep low C = 25.7

|Oct low C = 23.3

|Nov low C = 19.6

|Dec low C = 16.0

|Jan precipitation mm = 1

|Feb precipitation mm = 1

|Mar precipitation mm = 0

|Apr precipitation mm = 0

|May precipitation mm = 0

|Jun precipitation mm = 11

|Jul precipitation mm = 56

|Aug precipitation mm = 91

|Sep precipitation mm = 68

|Oct precipitation mm = 16

|Nov precipitation mm = 0

|Dec precipitation mm = 0

|year precipitation mm= 244

|source = Climate-Data.org, Climate data

|date=19 January 2018}}

The Coastal Zone, or Sub-Canarian Zone, extends the length of the approximately {{convert|754|km|mi|0|adj=on}} long Atlantic coast. Prevailing oceanic trade winds from the Canary Islands modify the influence of the harmattan, producing a humid but temperate climate. Rainfall here is minimal; in Nouadhibou it averages 30  mm annually and occurs between July and September. Temperatures are moderate, varying from mean maximums of {{convert|28|and|32|°C|°F|1}} for Nouadhibou and Nouakchott, respectively, to mean minimums of {{convert|16|and|19|°C|°F|1}}.

Battering surf and shifting sand banks characterize the entire length of the shoreline. The Ras Nouadhibou (formerly known as Cap Blanc) peninsula, which forms Dakhlet Nouadhibou (formerly Lévrier Bay) to the east, is {{convert|50|km|mi|0}} long and 13 km wide. The peninsula is administratively divided between Western Sahara and Mauritania, with the Mauritanian port and railhead of Nouadhibou located on the eastern shore. Dakhlet Nouadhibou, one of the largest natural harbours on the west coast of Africa, is {{convert|43|km|mi|0}} long and {{convert|32|km|mi|0}} wide at its broadest point. Fifty kilometres southeast of Ras Nouadhibou is Arguin. In 1455 the first Portuguese installation south of Cape Bojador (in the present-day Western Sahara) was established at Arguin. Farther south is the coastline's only significant promontory, {{convert|7|m|ft|0|adj=on}}-high Cape Timiris. From this cape to the marshy area around the mouth of the Senegal River, the coast is regular and marked only by an occasional high dune.

On coastal dunes vegetation is rare. At the foot of ridges, however, large tamarisk bushes, dwarf acacias, and swallowworts may be found. Some high grass, mixed with balsam, spurge, and spiny shrubs, grows in the central region. The north has little vegetation.

A recent global remote sensing analysis suggested that there were 494 km² of tidal flats in Mauritania, making it the 48th ranked country in terms of tidal flat area.{{cite journal |last1=Murray |first1=N.J. |last2=Phinn |first2=S.R. |last3=DeWitt |first3=M. |last4=Ferrari |first4=R. |last5=Johnston |first5=R. |last6=Lyons |first6=M.B. |last7=Clinton |first7=N. |last8=Thau |first8=D. |last9=Fuller |first9=R.A. |title=The global distribution and trajectory of tidal flats |journal=Nature |date=2019 |volume=565 |issue=7738 |pages=222–225 |doi=10.1038/s41586-018-0805-8 |pmid=30568300 |s2cid=56481043 |url=https://www.nature.com/articles/s41586-018-0805-8|url-access=subscription }}

{{Weather box

|width = auto

|location = Nouadhibou (extremes 1906–present)

|metric first = yes

|single line = yes

|Jan record high C = 33.6

|Feb record high C = 36.0

|Mar record high C = 38.0

|Apr record high C = 38.5

|May record high C = 39.4

|Jun record high C = 41.0

|Jul record high C = 39.7

|Aug record high C = 39.4

|Sep record high C = 41.3

|Oct record high C = 40.5

|Nov record high C = 37.4

|Dec record high C = 34.9

|year record high C = 41.3

|Jan high C = 24.3

|Feb high C = 25.4

|Mar high C = 27.0

|Apr high C = 26.2

|May high C = 26.5

|Jun high C = 27.9

|Jul high C = 27.2

|Aug high C = 28.2

|Sep high C = 30.5

|Oct high C = 29.9

|Nov high C = 27.3

|Dec high C = 24.7

|year high C = 27.1

|Jan mean C = 18.3

|Feb mean C = 19.2

|Mar mean C = 20.1

|Apr mean C = 19.9

|May mean C = 20.4

|Jun mean C = 22.8

|Jul mean C = 22.4

|Aug mean C = 23.5

|Sep mean C = 24.6

|Oct mean C = 23.3

|Nov mean C = 21.2

|Dec mean C = 19.2

|year mean C = 21.3

|Jan low C = 13.6

|Feb low C = 14.2

|Mar low C = 14.8

|Apr low C = 15.1

|May low C = 16.1

|Jun low C = 17.4

|Jul low C = 18.8

|Aug low C = 19.9

|Sep low C = 20.3

|Oct low C = 19.0

|Nov low C = 16.8

|Dec low C = 14.5

|year low C = 16.7

|Jan record low C = 4.0

|Feb record low C = 9.5

|Mar record low C = 10.0

|Apr record low C = 8.9

|May record low C = 9.8

|Jun record low C = 10.5

|Jul record low C = 10.8

|Aug record low C = 12.8

|Sep record low C = 13.4

|Oct record low C = 10.0

|Nov record low C = 10.0

|Dec record low C = 9.0

|year record low C = 4.0

|rain colour = green

|Jan rain mm = 2

|Feb rain mm = 3

|Mar rain mm = 2

|Apr rain mm = 1

|May rain mm = 1

|Jun rain mm = 1

|Jul rain mm = 1

|Aug rain mm = 3

|Sep rain mm = 5

|Oct rain mm = 3

|Nov rain mm = 2

|Dec rain mm = 1

|year rain mm = 23

|unit rain days = 1.0 mm

|Jan rain days = 0.3

|Feb rain days = 0.4

|Mar rain days = 0.3

|Apr rain days = 0.3

|May rain days = 0.1

|Jun rain days = 0.1

|Jul rain days = 0.2

|Aug rain days = 0.4

|Sep rain days = 0.7

|Oct rain days = 0.2

|Nov rain days = 0.2

|Dec rain days = 0.1

|year rain days = 3.1

|Jan humidity = 63

|Feb humidity = 68

|Mar humidity = 69

|Apr humidity = 72

|May humidity = 73

|Jun humidity = 74

|Jul humidity = 79

|Aug humidity = 78

|Sep humidity = 73

|Oct humidity = 72

|Nov humidity = 69

|Dec humidity = 66

|year humidity = 71

|Jan sun = 248.0

|Feb sun = 237.3

|Mar sun = 279.0

|Apr sun = 285.0

|May sun = 310.0

|Jun sun = 276.0

|Jul sun = 260.4

|Aug sun = 272.8

|Sep sun = 246.0

|Oct sun = 254.2

|Nov sun = 243.0

|Dec sun = 244.9

|year sun = 3156.6

|Jand sun = 8.0

|Febd sun = 8.4

|Mard sun = 9.0

|Aprd sun = 9.5

|Mayd sun = 10.0

|Jund sun = 9.2

|Juld sun = 8.4

|Augd sun = 8.8

|Sepd sun = 8.2

|Octd sun = 8.2

|Novd sun = 8.1

|Decd sun = 7.9

|yeard sun = 8.6

|source 1 = Deutscher Wetterdienst

{{cite web

| url = https://www.dwd.de/DWD/klima/beratung/ak/ak_614150_kt.pdf

| title = Klimatafel von Nouadhibou (Port Etienne) / Mauretanien

| work = Baseline climate means (1961-1990) from stations all over the world

| publisher = Deutscher Wetterdienst

| language = de

| access-date = 19 December 2018}}

|source 2 = Meteo Climat (record highs and lows)

{{cite web

| url = http://meteo-climat-bzh.dyndns.org/station-799-Nouadhibou.php

| title = Station Nouadhibou

| publisher = Météo Climat

| language = fr

| access-date = 19 December 2018}}

}}

{{Weather box

|location = Nouakchott (1981–2010, extremes 1934–2012)

|metric first = Y

|single line = Y

|Jan record high C = 39.9

|Feb record high C = 41.7

|Mar record high C = 44.0

|Apr record high C = 47.5

|May record high C = 47.0

|Jun record high C = 47.2

|Jul record high C = 47.5

|Aug record high C = 45.1

|Sep record high C = 45.5

|Oct record high C = 44.5

|Nov record high C = 42.3

|Dec record high C = 39.6

|year record high C = 47.5

|Jan high C = 29.1

|Feb high C = 30.8

|Mar high C = 33.5

|Apr high C = 34.8

|May high C = 34.3

|Jun high C = 34.7

|Jul high C = 32.4

|Aug high C = 33.0

|Sep high C = 36.1

|Oct high C = 36.7

|Nov high C = 34.0

|Dec high C = 31.0

|year high C = 33.4

|Jan mean C = 21.5

|Feb mean C = 23.0

|Mar mean C = 24.2

|Apr mean C = 24.3

|May mean C = 25.8

|Jun mean C = 26.7

|Jul mean C = 27.3

|Aug mean C = 28.4

|Sep mean C = 29.6

|Oct mean C = 28.8

|Nov mean C = 25.8

|Dec mean C = 22.8

|year mean C = 25.7

|Jan low C = 14.5

|Feb low C = 16.4

|Mar low C = 18.2

|Apr low C = 19.1

|May low C = 20.7

|Jun low C = 22.8

|Jul low C = 24.3

|Aug low C = 25.4

|Sep low C = 25.8

|Oct low C = 23.8

|Nov low C = 19.7

|Dec low C = 16.9

|year low C = 20.6

|Jan record low C = 3.9

|Feb record low C = 7.0

|Mar record low C = 5.0

|Apr record low C = 10.0

|May record low C = 13.0

|Jun record low C = 15.7

|Jul record low C = 15.0

|Aug record low C = 16.1

|Sep record low C = 17.0

|Oct record low C = 13.0

|Nov record low C = 9.3

|Dec record low C = 5.0

|year record low C = 3.9

|precipitation colour = green

|Jan precipitation mm = 0.7

|Feb precipitation mm = 1.5

|Mar precipitation mm = 0.2

|Apr precipitation mm = 0.1

|May precipitation mm = 0.3

|Jun precipitation mm = 1.9

|Jul precipitation mm = 6.3

|Aug precipitation mm = 36.8

|Sep precipitation mm = 36.3

|Oct precipitation mm = 6.3

|Nov precipitation mm = 2.0

|Dec precipitation mm = 2.8

|year precipitation mm = 95.2

|unit precipitation days = 1.0 mm

|Jan precipitation days = 0.2

|Feb precipitation days = 0.3

|Mar precipitation days = 0.0

|Apr precipitation days = 0.0

|May precipitation days = 0.0

|Jun precipitation days = 0.3

|Jul precipitation days = 0.8

|Aug precipitation days = 2.6

|Sep precipitation days = 3.0

|Oct precipitation days = 0.7

|Nov precipitation days = 0.2

|Dec precipitation days = 0.3

|year precipitation days = 8.3

|Jan humidity = 36

|Feb humidity = 39

|Mar humidity = 43

|Apr humidity = 49

|May humidity = 54

|Jun humidity = 60

|Jul humidity = 70

|Aug humidity = 72

|Sep humidity = 69

|Oct humidity = 55

|Nov humidity = 44

|Dec humidity = 35

|year humidity = 52

|Jan sun = 232.5

|Feb sun = 220.4

|Mar sun = 260.4

|Apr sun = 270.0

|May sun = 282.1

|Jun sun = 240.0

|Jul sun = 238.7

|Aug sun = 254.2

|Sep sun = 228.0

|Oct sun = 260.4

|Nov sun = 243.0

|Dec sun = 217.0

|year sun =

|Jand sun = 7.5

|Febd sun = 7.8

|Mard sun = 8.4

|Aprd sun = 9.0

|Mayd sun = 9.1

|Jund sun = 8.0

|Juld sun = 7.7

|Augd sun = 8.2

|Sepd sun = 7.6

|Octd sun = 8.4

|Novd sun = 8.1

|Decd sun = 7.0

|yeard sun = 8.1

|source 1 = Deutscher Wetterdienst{{cite web

| url = https://www.dwd.de/DWD/klima/beratung/ak/ak_614420_kt.pdf

| title = Klimatafel von Nouakchott / Mauretanien

| work = Baseline climate means (1961–1990) from stations all over the world

| publisher = Deutscher Wetterdienst

| language = de

| access-date = 18 December 2018

| archive-url = https://web.archive.org/web/20191009193845/https://www.dwd.de/DWD/klima/beratung/ak/ak_614420_kt.pdf

| archive-date = 9 October 2019

| url-status = live

}}

}}

Image:Passe de djouk.jpg; an increasingly arid area]]

The climate has altered drastically since the onset of the prolonged drought in the 1960s, part of a recurrent pattern of wet and dry cycles common to Sahelian Africa. Experts agree, however, that overgrazing, deforestation, denuding of ground cover around wells, poor farming methods, and overpopulation have aggravated the drought. In Mauritania the isohyet indicating annual rainfall of 150 millimetres—considered the minimum for pastoralism—has shifted southward about 100 kilometres to a point well south of Nouakchott. During the 1980s, the desert was advancing southward at an estimated rate of six kilometres a year. Each major climatic zone had shifted southward, and in some cases near-desert conditions had reached the banks of the Senegal River.

By the late 1980s, desertification had fundamentally altered agro-pastoral and human settlement patterns. Loss of ground cover in the Sahelian Zone had driven animals and people southward in search of food and water and had given rise to new fields of sand dunes. The advancing dunes threatened to engulf wells, villages, and roads; they had even invaded Nouakchott on their march to the sea. The government secured international help to stabilize the dune field around Nouakchott and planted 250,000 palm trees to create a barrier against the encroaching desert. To further combat desiccation, the government constructed dams on the Senegal River and its tributaries to increase the amount of cultivable land.

total:

{{convert|1,030,700|km2|sqmi|-1|abbr=on}}

land:

{{convert|1,030,700|km2|sqmi|-1|abbr=on}}

water:

{{convert|0|km2|sqmi|-1|abbr=on}}

total:

{{convert|5,074|km|mi|0}}

border countries:

Algeria {{convert|463|km|mi|0}}, Mali {{convert|2,237|km|mi|0}}, Senegal {{convert|813|km|mi|0}}, Western Sahara {{convert|1,561|km|mi|0}}

{{convert|754|km|mi nmi|0}}

territorial sea:

{{convert|12|nmi|km mi|1|abbr=on}}

contiguous zone:

{{convert|24|nmi|km mi|1|abbr=on|lk=in}}

continental shelf:

{{convert|200|nmi|km mi|1|abbr=on}} or to the edge of the continental margin

exclusive economic zone:

{{convert|200|nmi|km mi|1|abbr=on}}

lowest point:

Sebkha de Ndrhamcha {{convert|−5|m|ft|0}}

highest point:

Kediet ej Jill {{convert|915|m|ft|0}}

iron ore, gypsum, copper, phosphate, diamonds, gold, oil, fish

File:Oasis de Mhaïreth (15).jpg]]

arable land:

0.44%

permanent crops:

0.01%

other:

99.55% (2011){{citation needed|date=August 2018}}

450.1 km² (2004)

11.4 km³

hot, dry, dust/sand-laden sirocco wind blows primarily in March and April; periodic droughts

overgrazing, deforestation, and soil erosion aggravated by drought are contributing to desertification; very limited natural fresh water resources away from the Senegal which is the only perennial river; locust infestation

party to:

Biodiversity, Climate Change, Climate Change-Kyoto Protocol, Desertification, Endangered Species, Hazardous Wastes, Law of the Sea, Ozone Layer Protection, Ship Pollution, Wetlands, Whaling

signed, but not ratified:

none of the selected agreements

{{main|List of cities in Mauritania}}

The population is mainly concentrated in the cities of Nouakchott and Nouadhibou and along the Senegal River at the southern border of the country.

This is a list of the extreme points of Mauritania, the points that are farther north, south, east or west than any other location.

• Northernmost point – the tripoint with Algeria and Western Sahara, Tiris Zemmour Region
• Easternmost point – the tripoint with Algeria and Mali, Tiris Zemmour Region
• Southernmost point – the confluence of the Senegal River and the Karakoro River on the border with Mali, Guidimaka Region
• Westernmost point – unnamed location on the border with Western Sahara on the Ras Nouadhibou, peninsula, Dakhlet Nouadhibou Region

{{Reflist}}

• {{country study|country=Mauritania|abbr=mr}}

• [http://www.1uptravel.com/worldmaps/mauritania1.html Map] {{Webarchive|url=https://web.archive.org/web/20230512184124/http://www.1uptravel.com/worldmaps/mauritania1.html |date=2023-05-12 }}

{{Geography of Africa}}

{{Africa topic|Climate of}}

{{Mauritania topics}}

{{coord|20|00|N|12|00|W|type:country_source:ptwiki|display=title}}

{{DEFAULTSORT:Geography Of Mauritania}}