CROPWAT
Free
FAO's classic tool for crop water requirements and irrigation scheduling from climate and crop data.
Hydrology & Catchment AnalysisDormantIrrigationEvapotranspiration
4 tools · Topic
Evapotranspiration Calculation Tools
Whether you need FAO-56 Penman-Monteith reference ET for an irrigation schedule or actual ET from satellite data for a water balance, these packages cover it: standardised equation implementations, remote-sensing ET products and the utilities that fetch the weather data they require.
MIKE SHE
Commercial
DHI's integrated hydrological model — coupled overland, unsaturated, groundwater and channel flow.
Hydrology & Catchment AnalysisActiveGroundwater ModellingEvapotranspiration
SPEI (R package)
Open Source
The reference R implementation of SPEI and SPI from the index's own authors.
Climate & Change AnalysisStableDrought AnalysisR Hydrology
pyet
Open Source
Reference and potential evapotranspiration in Python — 20+ published methods, FAO-56 included, on pandas/xarray.
Hydrology & Catchment AnalysisActiveEvapotranspirationIrrigation