Climate averages 1991–2020
Missoula weather
by month.
See how the year changes. July has the highest average daily maximum; July (tied with August) has the lowest average monthly rainfall.
Pleasant-weather months by our simple rule: JulyAugustSeptember
Long-term climate patterns, not a forecast for a particular trip.
Across the year Missoula averages a daytime high of 13.4°C and a nighttime low of 3.1°C, with about 508 mm of rain on roughly 107 days. July is the warmest month (average high 28.8°C) and December the coolest (-0.1°C). May (tied with June) is the wettest month with 56 mm; July (tied with August) is the driest with 19 mm.
Months with pleasant weather by a simple rule (average high between 18°C and 29°C, average low of at least 5°C and at most 8 rain days): July, August and September. This looks at temperature and rain only, not humidity, wind, sea temperature or crowds.
The annual picture
A year in Missoula
Monthly precipitation
Average total · mmAverages from hourly ERA5 reanalysis data. Actual weather varies from year to year. How these numbers are calculated
Every month, side by side
Missoula climate table
| Month | Average highHigh / low | Average low | Precipitation mm/month | Wet days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 0.6°C-6.9°C | -6.9°C | 45 | 10.8 | 9.09 h |
| February | 2.7°C-5.7°C | -5.7°C | 41 | 9.9 | 10.310 h |
| March | 7.0°C-1.7°C | -1.7°C | 44 | 11.0 | 11.912 h |
| April | 11.4°C1.5°C | 1.5°C | 53 | 11.4 | 13.614 h |
| May | 17.9°C6.3°C | 6.3°C | 56 | 11.0 | 15.015 h |
| June | 22.2°C10.4°C | 10.4°C | 56 | 10.0 | 15.816 h |
| July | 28.8°C15.3°C | 15.3°C | 19 | 4.6 | 15.515 h |
| August | 28.6°C14.9°C | 14.9°C | 19 | 3.8 | 14.214 h |
| September | 22.5°C9.8°C | 9.8°C | 30 | 5.8 | 12.613 h |
| October | 13.6°C3.5°C | 3.5°C | 44 | 8.6 | 10.911 h |
| November | 5.2°C-2.3°C | -2.3°C | 50 | 10.0 | 9.49 h |
| December | -0.1°C-7.4°C | -7.4°C | 51 | 10.4 | 8.69 h |
Precipitation (rain or snow, as water) is the average of the 30 separate monthly totals. A wet day is a local calendar day with at least 1 mm of precipitation. Daylight is the calculated sunrise-to-sunset length, not measured sunshine.
Compare places
Nearby cities
- Spokane ValleyUnited States · 261 kmHigh 14.6°C · Low 4.2°C · 619 mm rain a year
- SpokaneUnited States · 274 kmHigh 15.1°C · Low 4.7°C · 551 mm rain a year
- LethbridgeCanada · 326 kmHigh 11.9°C · Low 1.4°C · 411 mm precipitation a year
- KennewickUnited States · 400 kmHigh 19.2°C · Low 7.8°C · 228 mm rain a year
- BoiseUnited States · 401 kmHigh 17.3°C · Low 5.8°C · 311 mm rain a year
- Tri-CitiesUnited States · 404 kmHigh 19.4°C · Low 7.9°C · 228 mm rain a year
- MeridianUnited States · 408 kmHigh 17.4°C · Low 5.8°C · 279 mm rain a year
- NampaUnited States · 422 kmHigh 18.0°C · Low 6.7°C · 279 mm rain a year
Read the numbers correctly
Climate, not a promise.
These patterns help compare months. They cannot tell you the weather on a specific day of your trip.
Sources, method and limitsWhat do the high and low temperatures mean?
We average the daily maximum and daily minimum for each calendar month over 1991–2020. They are not record extremes, a forecast range or temperatures at a fixed time of day.
How is a rain day counted?
A local calendar day (standard time, UTC-7, no daylight saving) with at least 1 mm of total precipitation counts as one rain day. We count these for each year and month, then average across 30 years. The average does not predict which days will be wet.
Where do the numbers come from?
ERA5-Land (temperature) and ERA5 (precipitation) reanalysis from the Copernicus Climate Change Service, read from the Open-Meteo open-data archive. Temperature comes from the 0.1° model cell at 46.90°, -114.00° (3 km from the city centre), adjusted up by 1.6°C for the difference between the city's elevation (978 m) and the cell's (1,228 m). Rain comes from the 0.25° cell at 46.75°, -114.00°. These are model estimates, not weather-station readings; coast, hills and city streets can differ.
Does this page show sunshine, humidity or sea temperature?
No. The data used here contain air temperature and precipitation only. Daylight hours are calculated from the city's latitude (sunrise to sunset), not measured sunshine.