Grand Rapids weather by month
Grand Rapids runs from about -2°C in January to 22°C in July, with July the wettest month at 117 mm.
warmest month
July
22°C
coolest month
January
-2°C
wettest month
July
117 mm
worst air month
February
12 µg/m³
The whole year, month by month.
| Month | Avg temp | Rain | Sun | PM2.5 |
|---|---|---|---|---|
| January | -2°C | 113 mm | 65 h | 7 |
| February | 1°C | 25 mm | 228 h | 12 |
| March | 4°C | 82 mm | 223 h | 9 |
| April | 10°C | 88 mm | 287 h | 7 |
| May | 17°C | 64 mm | 358 h | 7 |
| June | 21°C | 105 mm | 346 h | 7 |
| July | 22°C | 117 mm | 382 h | 10 |
| August | 22°C | 97 mm | 360 h | 10 |
| September | 20°C | 45 mm | 317 h | 8 |
| October | 13°C | 28 mm | 297 h | 5 |
| November | 7°C | 95 mm | 111 h | 5 |
| December | -1°C | 87 mm | 94 h | 7 |
About 3,068 hours of sun a year. Roughly 97 rainy days a year.
These are long-run climate normals, not a forecast. A given year can sit well outside them. PM2.5 is a global model: near the coast it counts sea salt as fine particulate and reads high against ground stations, sometimes by a factor of two. Use the shape of the year, not the absolute number.
where these numbers come from
- · Temperature, rainfall and sunshine: ECMWF ERA5 reanalysis climate normals via Open-Meteo (CC BY 4.0), fetched once and stored.
- · PM2.5: Copernicus CAMS reanalysis, monthly means. Modelled, not station readings; near coasts CAMS counts sea salt as PM2.5 and reads high.
Last reviewed 2026-05-24. Full method, licences and the list of sources we rejected are on the methodology page.