Solar DLI Calculator

What it does

A solar DLI calculator that turns monthly solar irradiance for a location into natural Daily Light Integral. It uses data from the NREL Solar Resource Database, or from the NASA POWER fallback when the proxy uses that source.

When to use it

Use it to compare natural DLI by month with crop requirements and see when supplemental lighting is needed, especially in winter. Best results with US locations.

How it calculates

• The location is found by city, ZIP code or latitude/longitude, then monthly global horizontal irradiance (kWh/m²/day) is fetched.
• Natural DLI (mol/m²/day) = GHI (kWh/m²/day) × 7.4
• Peak sun hours are set equal to daily GHI in kWh/m²/day.
• Seasonal variation = (peak monthly DLI − minimum monthly DLI) ÷ peak monthly DLI × 100

What you enter

City, State or Coordinates(latitude,longitude or ZIP code)

What you get

Avg Annual DLI(mol/m²/day)

Peak DLI (Summer) (mol/m²/day)

Min DLI (Winter) (mol/m²/day)

Seasonal Variation(%)

Monthly Solar Irradiance(kWh/m²/day)

Monthly Natural DLI(mol/m²/day)

Peak Sun Hours(hours)

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