Bozeman weather by month
Bozeman runs from about -6°C in January to 20°C in July, with May the wettest month at 101 mm.
warmest month
July
20°C
coolest month
January
-6°C
wettest month
May
101 mm
worst air month
August
10 µg/m³
The whole year, month by month.
| Month | Avg temp | Rain | Sun | PM2.5 |
|---|---|---|---|---|
| January | -6°C | 15 mm | 219 h | 4 |
| February | -3°C | 47 mm | 195 h | 6 |
| March | 0°C | 38 mm | 297 h | 7 |
| April | 5°C | 57 mm | 318 h | 7 |
| May | 8°C | 101 mm | 349 h | 7 |
| June | 15°C | 73 mm | 405 h | 6 |
| July | 20°C | 12 mm | 446 h | 7 |
| August | 19°C | 10 mm | 388 h | 10 |
| September | 15°C | 21 mm | 322 h | 8 |
| October | 9°C | 21 mm | 290 h | 4 |
| November | -1°C | 38 mm | 190 h | 5 |
| December | 0°C | 33 mm | 179 h | 3 |
About 3,598 hours of sun a year. Roughly 47 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.