CIMIS (California Irrigation Management Information System)
CIMIS data is available from www.ipm.ucdavis.edu/WEATHER/wxretrieve.html.
For more details about CIMIS, go to the CIMIS website at www.cimis.water.ca.gov.
Other sources
Any other source of
evapotranspiration data such as local weather station, farm operated weather
station or evaporation pan can be used. To learn about evaporation pans visit:
http://www.fao.org/docrep/X0490E/x0490e08.htm#pan%20evaporation%20method
http://www.agf.gov.bc.ca/resmgmt/publist/500series/577100-6.pdf