Flagstaff weather by month
Flagstaff runs from about -1°C in January to 23°C in July, with March the wettest month at 71 mm.
warmest month
July
23°C
coolest month
January
-1°C
wettest month
March
71 mm
worst air month
July
16 µg/m³
The whole year, month by month.
| Month | Avg temp | Rain | Sun | PM2.5 |
|---|---|---|---|---|
| January | -1°C | 33 mm | 250 h | 4 |
| February | 0°C | 62 mm | 257 h | 5 |
| March | 2°C | 71 mm | 321 h | 4 |
| April | 7°C | 26 mm | 365 h | 4 |
| May | 14°C | 9 mm | 410 h | 4 |
| June | 21°C | 46 mm | 397 h | 6 |
| July | 23°C | 30 mm | 408 h | 16 |
| August | 20°C | 60 mm | 365 h | 5 |
| September | 19°C | 12 mm | 359 h | 3 |
| October | 13°C | 42 mm | 321 h | 2 |
| November | 3°C | 10 mm | 284 h | 4 |
| December | 3°C | 0 mm | 283 h | 4 |
About 4,020 hours of sun a year. Roughly 40 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.