🌎 Reference Evapotranspiration (ETo) for the Next year — FAO-56 Penman-Monteith & NASA POWER

This calculator estimate daily ETo using the FAO-56 Penman-Monteith method (reference crop: grass) with climate data from NASA POWER for the next years. The tool can compute:

• Forecast ETo for the next year, using the average ETo of the same calendar days from the last 5 years.

If you need to know about the variable needed to estimate the ETO using the NASA-POWER system, please review the next page: Download NASA-POWER data to estimate Reference Evapotranspiration

Click on the map to select a location.

Mode: Forecast (next year, 5‑year average)

Start date:

End date:

FORECAST Based on 5‑year average (same calendar days)

Elevation (m): Leave empty or 0 to fetch automatically (NASA POWER / Open-Elevation).

ETo — daily & cumulative

📚 Bibliography

Allen, R. G., Pereira, L. S., Raes, D., & Smith, M. (1998). Crop evapotranspiration: Guidelines for computing crop requirements. FAO Irrigation and Drainage Paper 56. FAO, Rome.

Jiménez-Jiménez, S. I., Ojeda-Bustamante, W., Inzunza-Ibarra, M. A., & Marcial-Pablo, M. J. (2021). Analysis of the NASA-POWER system for estimating reference evapotranspiration in the Comarca Lagunera, Mexico. Ingeniería Agrícola y Biosistemas, 13(2), 201–226.

NASA. (2024). POWER Prediction Of Worldwide Energy Resources. https://power.larc.nasa.gov/

📝 How to cite

If you use this tool in academic work, please cite the sources above.

APA 7th:
Jiménez-Jiménez, S. I. (2026). Reference Evapotranspiration (ETo) for the Next year — FAO-56 Penman-Monteith & NASA POWER [https://www.hidraulicafacil.com.mx/2026/10/reference-evapotranspiration-eto-for.html]. HidraulicaFacil.