WEATHER · CLIMATE NORMALS · 1991–2020
Detroit Climate — Averages by Month
What the weather in Detroit, USaverages across a standard 30-year period. Each month's figure is the 1991–2020 mean temperature and total rainfall from the ERA5 reanalysis — the long-run normal a place settles around, not a forecast for any particular day.
Month-by-month normals
| Month | Avg temperature | Avg rainfall |
|---|---|---|
| January | -3.5 °C · coldest | 70.1 mm |
| February | -2.5 °C | 58.9 mm |
| March | 2.0 °C | 68.4 mm |
| April | 8.8 °C | 93.9 mm · wettest |
| May | 15.6 °C | 93.8 mm |
| June | 21.2 °C | 90.1 mm |
| July | 23.5 °C · warmest | 82.3 mm |
| August | 22.4 °C | 80.0 mm |
| September | 18.3 °C | 70.0 mm |
| October | 11.7 °C | 71.4 mm |
| November | 5.2 °C | 73.1 mm |
| December | -0.3 °C | 68.1 mm |
How to read these numbers
These are reanalysis normals, not readings from a single weather station. They come from the ERA5 0.25° (~25 km) global reanalysis grid, sampled at the grid cell nearest Detroit — centred at 42.25°N, 83.00°W. A reanalysis blends observations with a physics model onto an even grid, so a coastal or mountain city's cell can read a little cooler, warmer, wetter or drier than the city centre itself. The month-to-month shape — when it's hot, when it rains — is what these normals capture best.
“Normal” means the 1991–2020 average, the current World Meteorological Organization standard period. A normal is what a place tends toward over decades — any single day, month or year can and will depart from it.