Solar cycle 2

{{Use dmy dates|date=May 2024}}

{{Infobox Solar cycles

|image=Wilson effect original.jpg

|caption=Drawing of a sunspot from 1774, illustrating the Wilson effect

|cycle_num=2

|start_date=June 1766

|end_date=June 1775

|duration=9

|max_count=193.0

|max_count_date=September 1769

|min_count=18.6

|prev_name=Solar cycle 1

|prev_dates=1755–1766

|next_name=Solar cycle 3

|next_dates=1775–1784

}}

Solar cycle 2 was the second solar cycle since 1755, when extensive recording of sunspot activity began.{{citation|doi=10.1023/A:1014296529097|year=2002|last1=Kane|first1=R.P.|title=Some Implications Using the Group Sunspot Number Reconstruction|journal=Solar Physics|volume=205|issue=2|pages=383–401|bibcode=2002SoPh..205..383K}}{{cite web | title=The Sun: Did You Say the Sun Has Spots? | url=http://www.spacetoday.org/SolSys/Sun/Sunspots.html | publisher=Space Today Online | accessdate=12 August 2010}} The solar cycle lasted 9 years, beginning in June 1766 and ending in June 1775. The maximum smoothed sunspot number observed during the solar cycle was 193.0 (September 1769), and the starting minimum was 18.6.{{cite web |title=SIDC Monthly Smoothed Sunspot Number |url=https://www.sidc.be/SILSO/datafiles }}

Sunspot observations by Alexander Wilson during this period established the Wilson effect.