Zambretti Forecaster

File:Zambretti Forecaster.jpg The Zambretti Forecaster is a weather forecasting instrument used in conjunction with a barometer. It interprets the reading of a barometer into one forecast from a large selection of permutations after making allowances for variable factors. These include wind direction, a rising, falling or steady barometer, and the season.{{Cite web

|url=http://www.meteormetrics.com/zambretti.htm

|archive-url=https://web.archive.org/web/20110610213848/http://www.meteormetrics.com/zambretti.htm

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|archive-date=2011-06-10

|website=Meteor Metrics

|title=Zambretti Algorithm

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Negretti and Zambra were scientific instrument makers, noted for their barometers. The Forecaster was produced in 1915 as a portable forecaster which needed minimal instrumentation, a simple barometer and an observation of the wind direction, and was easy to calculate with. It was produced as a small disc calculator made of overlaid discs of ivorine, an early plastic.{{Cite web

|title=Zambretti Forecaster

|website=Whitby Weather

|url=http://www.whitbyweather.com/index.php?p=1_56_Zambretti-Forecaster

}} Despite its simplicity, it achieved 90% accuracy for 12 hour forecasts. The original Zambretti algorithm has since been implemented in a number of electronic forecasters.