Calculator › Chicago, Illinois
Solar panels in Chicago, Illinois
Chicago receives 4.11 peak sun hours a day and 1,500 kWh/m² of solar energy a year. That is measured satellite data for Chicago's coordinates, not a national average — and it changes the panel count.
Chicago solar data
4.11peak sun hours/day
1,500annual irradiance (kWh/m²)
1.36kWh/day from one 400 W panel
495kWh/year from one 400 W panel
Monthly solar irradiance in Chicago
| Month | Peak sun hours/day | Share of year |
|---|---|---|
| January | 1.56 | 0.1 |
| February | 3.28 | 0.3 |
| March | 3.87 | 0.3 |
| April | 4.72 | 0.4 |
| May | 6.11 | 0.5 |
| June | 6.31 | 0.5 |
| July | 6.02 | 0.5 |
| August | 5.62 | 0.5 |
| September | 4.81 | 0.4 |
| October | 3.77 | 0.3 |
| November | 1.71 | 0.1 |
| December | 1.39 | 0.1 |
Source: NASA POWER daily point API, parameter ALLSKY_SFC_SW_DWN (global horizontal irradiance), year 2024. Coordinates 41.8781, -87.6298.
How many solar panels does Chicago need?
For a typical US household using 900 kWh a month, Chicago needs about 23 panels of 400 W (8.84 kWp), with a south-facing roof. That is more panels than the same household would need in a city with 4.5 peak sun hours.