August is one of the warmer months of the year in Missoula, with average highs near 25.5°C and lows around 9.5°C (mean 17.5°C). It is one of the drier months, averaging 39 mm of rainfall and 53% relative humidity across the period.
August is one of the warmer months of the year in Missoula. Across 45 years of records, the warmest August in Missoula was 2022 — when the month averaged 20.8°C — while the coldest was 1993 at 13.8°C. Typical August days reach 25.5°C with nights near 9.5°C. The long-term trend is warming, about 0.3°C per decade.
August is one of the drier months in Missoula, averaging 39 mm of rainfall. The wettest August on record was 1985 with 89 mm, while the driest was 2001 at 2 mm.
Relative humidity in Missoula during August averages 53%. The most humid August was 1993 at 65%, and the least humid was 2001 at 41%.
August receives about 6.1 kWh/m²/day of solar energy in Missoula. The sunniest Augusts were 1998, 2001 and 2011 at 6.8 kWh/m²/day, and the cloudiest was 2021 at 5.3.
Average wind speed in Missoula during August is 0.3 m/s. The windiest Augusts were 2020, 2021 and 2022, among others at 0.3 m/s, while the calmest were 2023, 2024 and 2025, among others at 0.2 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 17.0°C | 17.1°C | 17.3°C | 17.9°C | 18.7°C | +1.7°C |
| Avg High | 25.1°C | 25.1°C | 25.6°C | 25.9°C | 26.3°C | +1.2°C |
| Avg Low | 8.9°C | 9.2°C | 9.0°C | 9.9°C | 11.0°C | +2.1°C |
| Avg Rain | 44 mm | 37 mm | 37 mm | 32 mm | 49 mm | +5 mm |
August temperatures in Missoula have risen by about 1.2°C between 1981–1985 and 2021–2025.
August has ranged from a record low of -0.7°C (1993) to a record high of 36.8°C (2003).
Rainfall in August is one of the drier months, averaging 39 mm, with a wettest year of 89 mm.
One of the best times to visit Missoula
August is one of the best times to visit Missoula. Expect days averaging 25.5°C and nights around 9.5°C (mean 17.5°C) — warmer than Missoula's yearly average — with moderate rainfall (39 mm), so conditions are generally comfortable for sightseeing and outdoor plans.
| Year | Avg High | Avg Temp | Avg Low | Hottest Day | Coldest Day | Rainfall | Humidity | Wind | Solar |
|---|---|---|---|---|---|---|---|---|---|
| 2025 | 26.1°C | 18.7°C | 11.2°C | 33.3°C | 5.6°C | 53 mm | 58% | 0.2 m/s | 5.7 |
| 2024 | 26.4°C | 18.3°C | 10.2°C | 34.1°C | 2.9°C | 53 mm | 56% | 0.2 m/s | 5.7 |
| 2023 | 26.2°C | 19.0°C | 11.7°C | 34.3°C | 7.8°C | 85 mm | 57% | 0.2 m/s | 5.4 |
| 2022 🔥 | 29.1°C | 20.8°C | 12.6°C | 34.8°C | 7.4°C | 27 mm | 48% | 0.3 m/s | 6.4 |
| 2021 | 24.6°C | 17.3°C | 9.9°C | 33.2°C | 3.8°C | 57 mm | 55% | 0.3 m/s | 5.3 |
| 2020 | 25.5°C | 17.9°C | 10.3°C | 32.7°C | 5.0°C | 21 mm | 55% | 0.3 m/s | 6.3 |
| 2019 | 25.8°C | 18.2°C | 10.6°C | 33.2°C | 6.3°C | 47 mm | 54% | 0.3 m/s | 6 |
| 2018 | 24.7°C | 17.1°C | 9.5°C | 36.8°C | 1.0°C | 28 mm | 53% | 0.3 m/s | 6 |
| 2017 | 26.6°C | 18.6°C | 10.5°C | 32.4°C | 7.5°C | 16 mm | 47% | 0.3 m/s | 6 |
| 2016 | 25.5°C | 17.2°C | 8.8°C | 32.8°C | 3.9°C | 25 mm | 50% | 0.3 m/s | 6.3 |
| 2015 | 27.1°C | 18.7°C | 10.4°C | 34.9°C | 3.5°C | 15 mm | 45% | 0.3 m/s | 5.7 |
| 2014 | 24.9°C | 17.6°C | 10.3°C | 33.4°C | 4.0°C | 60 mm | 60% | 0.3 m/s | 5.7 |
| 2013 | 27.8°C | 19.3°C | 10.9°C | 31.8°C | 5.9°C | 37 mm | 53% | 0.3 m/s | 6 |
| 2012 | 27.5°C | 18.6°C | 9.8°C | 32.5°C | 4.6°C | 17 mm | 47% | 0.3 m/s | 6.7 |
| 2011 | 25.8°C | 18.0°C | 10.2°C | 31.1°C | 5.6°C | 26 mm | 55% | 0.3 m/s | 6.8 |
| 2010 | 23.1°C | 15.6°C | 8.0°C | 32.5°C | 3.1°C | 49 mm | 59% | 0.2 m/s | 6.2 |
| 2009 | 23.8°C | 16.4°C | 9.0°C | 31.9°C | 3.3°C | 71 mm | 61% | 0.3 m/s | 5.7 |
| 2008 | 24.4°C | 16.1°C | 7.9°C | 34.1°C | 2.1°C | 67 mm | 56% | 0.3 m/s | 6.1 |
| 2007 | 26.1°C | 17.4°C | 8.7°C | 32.3°C | 3.4°C | 17 mm | 45% | 0.3 m/s | 6.3 |
| 2006 | 25.3°C | 17.0°C | 8.7°C | 34.0°C | 2.2°C | 40 mm | 47% | 0.3 m/s | 6.3 |
| 2005 | 25.6°C | 17.1°C | 8.6°C | 32.8°C | 2.4°C | 19 mm | 47% | 0.3 m/s | 6.6 |
| 2004 | 24.4°C | 16.6°C | 8.8°C | 32.4°C | 3.8°C | 72 mm | 60% | 0.2 m/s | 5.7 |
| 2003 | 28.9°C | 20.1°C | 11.3°C | 36.8°C | 4.4°C | 26 mm | 45% | 0.3 m/s | 6.2 |
| 2002 | 22.5°C | 14.9°C | 7.3°C | 26.7°C | 3.8°C | 44 mm | 58% | 0.2 m/s | 6.1 |
| 2001 | 28.6°C | 19.7°C | 10.8°C | 33.8°C | 5.1°C | 2 mm | 41% | 0.3 m/s | 6.8 |
| 2000 | 26.6°C | 17.9°C | 9.3°C | 35.4°C | 4.5°C | 12 mm | 42% | 0.3 m/s | 6.7 |
| 1999 | 26.3°C | 18.1°C | 9.9°C | 32.9°C | 3.2°C | 38 mm | 56% | 0.2 m/s | 5.8 |
| 1998 | 27.3°C | 18.9°C | 10.6°C | 33.6°C | 5.2°C | 16 mm | 50% | 0.3 m/s | 6.8 |
| 1997 | 24.2°C | 16.6°C | 8.9°C | 31.0°C | 3.8°C | 37 mm | 63% | 0.2 m/s | 6.2 |
| 1996 | 24.0°C | 16.4°C | 8.7°C | 33.4°C | 1.2°C | 46 mm | 55% | 0.3 m/s | 6 |
| 1995 | 23.4°C | 15.3°C | 7.2°C | 30.9°C | 1.0°C | 37 mm | 57% | 0.3 m/s | 5.9 |
| 1994 | 27.8°C | 18.8°C | 9.8°C | 34.7°C | 5.0°C | 8 mm | 43% | 0.2 m/s | 6.5 |
| 1993 ❄️ | 20.7°C | 13.8°C | 6.9°C | 28.8°C | -0.7°C | 65 mm | 65% | 0.3 m/s | 5.7 |
| 1992 | 24.6°C | 16.8°C | 8.9°C | 33.1°C | 0.1°C | 29 mm | 47% | 0.3 m/s | 6.3 |
| 1991 | 27.2°C | 19.0°C | 10.9°C | 34.8°C | 7.5°C | 26 mm | 50% | 0.3 m/s | 6.5 |
| 1990 | 25.0°C | 17.4°C | 9.9°C | 33.8°C | 3.4°C | 67 mm | 60% | 0.2 m/s | 5.6 |
| 1989 | 22.2°C | 14.9°C | 7.6°C | 30.9°C | 1.6°C | 75 mm | 63% | 0.2 m/s | 5.5 |
| 1988 | 26.0°C | 17.1°C | 8.2°C | 32.3°C | 3.1°C | 12 mm | 42% | 0.3 m/s | 6.7 |
| 1987 | 22.4°C | 14.6°C | 6.8°C | 30.6°C | 1.8°C | 42 mm | 54% | 0.3 m/s | 6.1 |
| 1986 | 26.7°C | 18.4°C | 10.2°C | 32.8°C | 4.7°C | 48 mm | 47% | 0.3 m/s | 6.4 |
| 1985 🌧️ | 21.6°C | 14.1°C | 6.6°C | 28.9°C | 1.7°C | 89 mm | 57% | 0.3 m/s | 5.6 |
| 1984 | 26.6°C | 18.2°C | 9.8°C | 33.2°C | 2.3°C | 49 mm | 51% | 0.3 m/s | 5.9 |
| 1983 | 26.7°C | 19.0°C | 11.3°C | 34.8°C | 6.6°C | 37 mm | 56% | 0.3 m/s | — |
| 1982 | 25.2°C | 17.4°C | 9.6°C | 32.4°C | 3.3°C | 21 mm | 54% | 0.3 m/s | — |
| 1981 | 28.3°C | 19.3°C | 10.3°C | 35.8°C | 4.5°C | 22 mm | 47% | 0.2 m/s | — |
Actual recorded August data for each year, 1981–2025 — sourced from NASA POWER.
The average high in August is around 25.5°C with lows near 9.5°C (mean 17.5°C), based on 45 years of NASA POWER data.
August averages 39 mm of rainfall in Missoula, one of the drier months. The wettest on record was 89 mm in 1985.
The hottest August reached 36.8°C in 2003. The coldest dipped to -0.7°C in 1993.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average August temperatures have risen by about 1.2°C. Daytime highs moved from 25.7°C to 26.5°C and overnight lows from 9.5°C to 11.1°C over the same span.
August is one of the warmer months of the year in Missoula and one of the drier months, so plan for around 25.5°C daytime highs and 9.5°C at night.
Not quite — August is the 12th coolest month in Missoula, averaging 17.5°C.
For August in Missoula, pack light layers you can adjust through the day, with typical highs of 25.5°C and lows of 9.5°C.
Relative humidity in August averages 53% — relatively dry.
Average wind speed in August is 0.3 m/s. The windiest August on record averaged 0.3 m/s (1982).
The wettest August on record was 1985 with 89 mm. On average, August sees 39 mm.
All figures are derived from NASA POWER (Prediction Of Worldwide Energy Resources), based on MERRA-2 satellite reanalysis, covering 1981–2025.
Explore how the weather in Missoula behaves each August, based on 45 years of NASA POWER climate data from 1981 to 2025. This page breaks down average temperatures, rainfall, humidity, wind and solar radiation for August specifically, along with year-by-year records and how the month has changed over the decades.
