Missoula weather in September: Missoula, Montana: normal highs, lows, rain and records for September
Missoula in September has a normal high of 73°F and a normal low of 42°F, a daily mean of 58°F, falling from 79°F on the 1st to 66°F by the 30th. Measurable precipitation falls on 7 days in a normal September, 0.96 inches in all. (NOAA 1991-2020 normals)
In metric: a normal high of 23°C and low of 6°C, 24 mm of precipitation and 0 cm of snow in September.
- NOAA stationMissoula International Airport
- Station IDUSW00024153
- Location46.92°N 114.09°W
- Elevation3,192 ft (973 m)
- From the center4 miles
- Population78,204
- Jan 32° 18°
- Feb 37° 21°
- Mar 48° 27°
- Apr 56° 32°
- May 66° 40°
- Jun 73° 46°
- Jul 85° 52°
- Aug 84° 50°
- Sep 73° 42°
- Oct 56° 32°
- Nov 40° 25°
- Dec 31° 18°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
How warm is Missoula in September?
The normal high is 73°F and the normal low 42°F, for a daily mean of 57.5°F. September is 9.7°F cooler than August and 13.4°F warmer than October. September is the 4th warmest month of the year in Missoula and the 7th wettest. Across the month the normal high falls 13°F, from 79°F on September 1 to 66°F on September 30. From one year to the next September's mean temperature typically moves about 2.4°F either way (NOAA's standard deviation), so roughly two Septembers in three average between 55°F and 60°F.
Bars above: each day's normal high to low. Columns below: the chance of 0.01 inch or more of precipitation that day, on a scale of 0 to 100% (highest 26%).
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in |
|---|---|---|---|---|
| September 1 | 79°F | 47°F | 22% | 10% |
| September 8 | 76°F | 45°F | 23% | 10% |
| September 15 | 73°F | 43°F | 24% | 10% |
| September 22 | 70°F | 41°F | 25% | 10% |
| September 30 | 66°F | 38°F | 26% | 10% |
Every day of September: normal high, low and chance of precipitation (warmest afternoon September 1, coldest night September 30)
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in | Daylight |
|---|---|---|---|---|---|
| September 1 | 79°F | 47°F | 22% | 10% | 13 h 20 min |
| September 2 | 78°F | 46°F | 22% | 10% | 13 h 20 min |
| September 3 | 78°F | 46°F | 22% | 10% | 13 h 20 min |
| September 4 | 78°F | 46°F | 23% | 10% | 13 h 10 min |
| September 5 | 77°F | 45°F | 23% | 10% | 13 h 10 min |
| September 6 | 77°F | 45°F | 23% | 10% | 13 h 10 min |
| September 7 | 76°F | 45°F | 23% | 10% | 13 h |
| September 8 | 76°F | 45°F | 23% | 10% | 13 h |
| September 9 | 76°F | 44°F | 23% | 10% | 13 h |
| September 10 | 75°F | 44°F | 23% | 10% | 12 h 50 min |
| September 11 | 75°F | 44°F | 24% | 10% | 12 h 50 min |
| September 12 | 74°F | 44°F | 24% | 10% | 12 h 50 min |
| September 13 | 74°F | 43°F | 24% | 10% | 12 h 50 min |
| September 14 | 74°F | 43°F | 24% | 10% | 12 h 40 min |
| September 15 | 73°F | 43°F | 24% | 10% | 12 h 40 min |
| September 16 | 73°F | 42°F | 24% | 10% | 12 h 40 min |
| September 17 | 72°F | 42°F | 25% | 10% | 12 h 30 min |
| September 18 | 72°F | 42°F | 25% | 10% | 12 h 30 min |
| September 19 | 71°F | 42°F | 25% | 10% | 12 h 30 min |
| September 20 | 71°F | 41°F | 25% | 10% | 12 h 20 min |
| September 21 | 70°F | 41°F | 25% | 10% | 12 h 20 min |
| September 22 | 70°F | 41°F | 25% | 10% | 12 h 20 min |
| September 23 | 69°F | 40°F | 25% | 10% | 12 h 10 min |
| September 24 | 69°F | 40°F | 25% | 10% | 12 h 10 min |
| September 25 | 68°F | 40°F | 25% | 10% | 12 h 10 min |
| September 26 | 68°F | 39°F | 26% | 10% | 12 h |
| September 27 | 67°F | 39°F | 26% | 10% | 12 h |
| September 28 | 67°F | 39°F | 26% | 10% | 12 h |
| September 29 | 66°F | 38°F | 26% | 10% | 11 h 50 min |
| September 30 | 66°F | 38°F | 26% | 10% | 11 h 50 min |
- Normal high
- 73°FSeptember average
- Normal low
- 42°FSeptember average
- Precipitation
- 0.96 inmonth total
- Days with precipitation
- 70.01 inch or more
- Snowfall
- 0.1 inmonth total
- Days at 90°F or more
- 1
- Nights at 32°F or colder
- 2
- Daylight
- 13 h 20 min to 11 h 50 minSeptember 1 to September 30
- Days at 70°F or more
- 19
- Days at 80°F or more
- 10
- Sunshine
- 79%of clear-sky sunlight (NASA)
Source: NOAA NCEI 1991-2020 daily normals, station USW00024153; monthly normals. Daylight is computed from the place's latitude with NOAA's solar equations.
Does it rain or snow in Missoula in September?
On a given September day the chance of 0.01 inch or more is 24% on average, highest around September 30 (26%). In all, 0.96 in falls on 7 days of a normal September.
In a normal September in Missoula, 1 days reach 90°F, 2 nights fall to freezing and snowfall averages 0.1 inches.
Source: NOAA NCEI 1991-2020 daily and monthly normals, station USW00024153.
How humid and windy is Missoula in September?
At 3 p.m. the normal temperature is 65°F with 34% relative humidity and a dew point of 36°F; at 6 a.m. it is 41°F with 78% humidity. The wind averages 4.7 mph, most often from the west-northwest in the afternoon. A dew point under 50°F feels dry.
| Time | Temperature | Dew point | Humidity | Wind | Clear or few clouds |
|---|---|---|---|---|---|
| 6 a.m. | 41°F | 35°F | 78% | 2.9 mph | 68% |
| 9 a.m. | 47°F | 37°F | 68% | 3.3 mph | 67% |
| noon | 58°F | 37°F | 45% | 5.0 mph | 69% |
| 3 p.m. | 65°F | 36°F | 34% | 7.1 mph | 68% |
| 6 p.m. | 61°F | 37°F | 41% | 7.5 mph | 66% |
| 9 p.m. | 52°F | 37°F | 56% | 4.4 mph | 69% |
Source: NOAA NCEI 1991-2020 hourly normals, station USW00024153. Hourly normals exist only for NOAA's first-order stations; a dash where NOAA publishes no value for that hour (the sky at some hours).
What are the records for September in Missoula?
The warmest September temperature on Missoula's official record (since 1893) is 99°F, on September 1, 1967; the coldest is 15°F, on September 25, 1926. The wettest September brought 3.74 in (1908); the snowiest, 7.6 inches (1945).
The September mean against the 1991-2020 normal of 57.5°F: 2021 58.8°F (+1.3), 2022 62.5°F (+5.0), 2023 60.1°F (+2.6), 2024 61.9°F (+4.4), 2025 64.2°F (+6.7), 2026 57.1°F (−0.4). 5 of 6 ran warmer than normal.
| September | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 58.8°F | +1.3°F | 0.57 in |
| 2022 | 62.5°F | +5.0°F | 1.42 in |
| 2023 | 60.1°F | +2.6°F | 1.68 in |
| 2024 | 61.9°F | +4.4°F | 1.05 in |
| 2025 | 64.2°F | +6.7°F | 0.41 in |
| 2026 | 57.1°F | −0.4°F | 2.13 in |
Source: records: ACIS, NWS threaded record MSOthr; recent months: ACIS, station USW00024153. Records and recent months use complete months only.
How does September in Missoula compare across Montana?
Across the 141 places PlainClimate covers in Montana, September normal highs run from 62°F in Cooke City to 79°F in Hardin; Missoula's is 73°F.
Source: NOAA NCEI 1991-2020 monthly normals for every station in the state.