Compare calculators
Both calculators run independently — change the inputs on either side to compare results.
Climate
Solar Radiation Calculator
Estimate top-of-atmosphere solar irradiance at solar noon for a given latitude, day of year, and solar declination. Returns watts per square metre on a horizontal surface, before atmospheric attenuation.
Fill in the required fields to see your result.
Climate
Evapotranspiration Calculator
Estimate monthly potential evapotranspiration (PET) from average temperature, daylight hours, and days in the month using a simplified Thornthwaite-style formula. Returns millimetres of water lost per month.
Fill in the required fields to see your result.
Key differences
| Solar Radiation Calculator | Evapotranspiration Calculator | |
|---|---|---|
| Category | Climate | Climate |
| Inputs required | 3 | 3 |
| Result | Solar Radiation (W/m²) | Potential Evapotranspiration (mm/month) |
| What it does | Estimate top-of-atmosphere solar irradiance at solar noon for a given latitude, day of year, and solar declination. Returns watts per square metre on a horizontal surface, before atmospheric attenuation. | Estimate monthly potential evapotranspiration (PET) from average temperature, daylight hours, and days in the month using a simplified Thornthwaite-style formula. Returns millimetres of water lost per month. |