Bozeman weather in September: Bozeman, Montana: normal highs, lows, rain and records for September
Bozeman in September has a normal high of 73°F and a normal low of 40°F, a daily mean of 56°F, falling from 79°F on the 1st to 66°F by the 30th. Measurable precipitation falls on 7 days in a normal September, 1.00 inches in all. (NOAA 1991-2020 normals)
In metric: a normal high of 23°C and low of 4°C, 25 mm of precipitation in September.
- NOAA stationBozeman Gallatin Field
- Station IDUSW00024132
- Location45.79°N 111.16°W
- Elevation4,427 ft (1,349 m)
- Population57,894
- Jan 32° 10°
- Feb 36° 13°
- Mar 46° 22°
- Apr 55° 29°
- May 65° 38°
- Jun 74° 44°
- Jul 85° 49°
- Aug 84° 47°
- Sep 73° 40°
- Oct 58° 29°
- Nov 42° 18°
- Dec 32° 10°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
How warm is Bozeman in September?
The normal high is 73°F and the normal low 40°F, for a daily mean of 56.3°F. September is 9.5°F cooler than August and 12.9°F warmer than October. September is the 4th warmest month of the year in Bozeman and the 6th 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 2.2°F either way (NOAA's standard deviation), so roughly two Septembers in three average between 54°F and 59°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 25%).
| Day | High | Low | Chance of 0.01 in | Chance of 0.10 in |
|---|---|---|---|---|
| September 1 | 79°F | 43°F | 24% | 10% |
| September 8 | 76°F | 42°F | 25% | 11% |
| September 15 | 74°F | 40°F | 25% | 11% |
| September 22 | 70°F | 38°F | 25% | 11% |
| September 30 | 66°F | 35°F | 25% | 11% |
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 | 43°F | 24% | 10% | 13 h 20 min |
| September 2 | 78°F | 43°F | 24% | 10% | 13 h 20 min |
| September 3 | 78°F | 43°F | 24% | 10% | 13 h 10 min |
| September 4 | 78°F | 43°F | 24% | 10% | 13 h 10 min |
| September 5 | 77°F | 42°F | 24% | 10% | 13 h 10 min |
| September 6 | 77°F | 42°F | 24% | 10% | 13 h 10 min |
| September 7 | 77°F | 42°F | 24% | 11% | 13 h |
| September 8 | 76°F | 42°F | 25% | 11% | 13 h |
| September 9 | 76°F | 41°F | 25% | 11% | 13 h |
| September 10 | 76°F | 41°F | 25% | 11% | 12 h 50 min |
| September 11 | 75°F | 41°F | 25% | 11% | 12 h 50 min |
| September 12 | 75°F | 41°F | 25% | 11% | 12 h 50 min |
| September 13 | 74°F | 40°F | 25% | 11% | 12 h 40 min |
| September 14 | 74°F | 40°F | 25% | 11% | 12 h 40 min |
| September 15 | 74°F | 40°F | 25% | 11% | 12 h 40 min |
| September 16 | 73°F | 40°F | 25% | 11% | 12 h 30 min |
| September 17 | 73°F | 39°F | 25% | 11% | 12 h 30 min |
| September 18 | 72°F | 39°F | 25% | 11% | 12 h 30 min |
| September 19 | 72°F | 39°F | 25% | 11% | 12 h 20 min |
| September 20 | 71°F | 38°F | 25% | 11% | 12 h 20 min |
| September 21 | 71°F | 38°F | 25% | 11% | 12 h 20 min |
| September 22 | 70°F | 38°F | 25% | 11% | 12 h 10 min |
| September 23 | 70°F | 38°F | 25% | 11% | 12 h 10 min |
| September 24 | 69°F | 37°F | 25% | 11% | 12 h 10 min |
| September 25 | 69°F | 37°F | 25% | 11% | 12 h 10 min |
| September 26 | 68°F | 37°F | 25% | 11% | 12 h |
| September 27 | 68°F | 36°F | 25% | 11% | 12 h |
| September 28 | 67°F | 36°F | 25% | 11% | 12 h |
| September 29 | 67°F | 36°F | 25% | 11% | 11 h 50 min |
| September 30 | 66°F | 35°F | 25% | 11% | 11 h 50 min |
- Normal high
- 73°FSeptember average
- Normal low
- 40°FSeptember average
- Precipitation
- 1.00 inmonth total
- Days with precipitation
- 70.01 inch or more
- Days at 90°F or more
- 2
- Nights at 32°F or colder
- 5
- Daylight
- 13 h 20 min to 11 h 50 minSeptember 1 to September 30
- Days at 70°F or more
- 20
- Days at 80°F or more
- 10
- Sunshine
- 79%of clear-sky sunlight (NASA)
Source: NOAA NCEI 1991-2020 daily normals, station USW00024132; monthly normals. Daylight is computed from the place's latitude with NOAA's solar equations.
Does it rain in Bozeman in September?
On a given September day the chance of 0.01 inch or more is 25% on average, highest around September 30 (25%). In all, 1.00 in falls on 7 days of a normal September.
In a normal September in Bozeman, 2 days reach 90°F and 5 nights fall to freezing.
Source: NOAA NCEI 1991-2020 daily and monthly normals, station USW00024132.
How humid and windy is Bozeman in September?
At 3 p.m. the normal temperature is 64°F with 31% relative humidity and a dew point of 33°F; at 6 a.m. it is 38°F with 78% humidity. The wind averages 5.5 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. | 38°F | 32°F | 78% | 4.2 mph | 69% |
| 9 a.m. | 49°F | 35°F | 59% | 3.3 mph | 67% |
| noon | 60°F | 34°F | 38% | 5.8 mph | 62% |
| 3 p.m. | 64°F | 33°F | 31% | 7.0 mph | 62% |
| 6 p.m. | 58°F | 34°F | 41% | 6.3 mph | 65% |
| 9 p.m. | 48°F | 35°F | 60% | 6.5 mph | 67% |
Source: NOAA NCEI 1991-2020 hourly normals, station USW00024132. 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 Bozeman?
The warmest September temperature on this station's record (since 1941) is 100°F, on September 5, 2020; the coldest is 15°F, on September 30, 1985. The wettest September brought 4.50 in (1947); the snowiest, 5.0 inches (1977).
The September mean against the 1991-2020 normal of 56.3°F: 2021 57.8°F (+1.5), 2022 60.5°F (+4.2), 2023 58.9°F (+2.6), 2024 60.9°F (+4.6), 2025 60.5°F (+4.2), 2026 57.8°F (+1.5). 6 of 6 ran warmer than normal.
| September | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 57.8°F | +1.5°F | 0.12 in |
| 2022 | 60.5°F | +4.2°F | 1.25 in |
| 2023 | 58.9°F | +2.6°F | 1.62 in |
| 2024 | 60.9°F | +4.6°F | 2.35 in |
| 2025 | 60.5°F | +4.2°F | 1.21 in |
| 2026 | 57.8°F | +1.5°F | 0.90 in |
Source: records: ACIS, station USW00024132; recent months: ACIS, station USW00024132. Records and recent months use complete months only.
How does September in Bozeman 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; Bozeman's is 73°F.
Source: NOAA NCEI 1991-2020 monthly normals for every station in the state.