Average Temperatures for Montana in September

Average temperatures for September at cities, towns, parks and lakes throughout Montana are listed below in degrees Fahrenheit and Celsius.

You can jump to a separate table for each region of the state: Northwestern, Southwestern, South - Central and Eastern Montana.

The tables give the normals for maximum and minimum temperatures based on weather data collected from 1991 to 2020 by the US National Centers for Environmental Information.

Northwestern Montana

Average September temperatures
High °F Low °F Place High °C Low °C
69 40 Cut Bank 20 5
63 38 East Glacier Park 17 3
68 36 Gibson Reservoir Dam 20 2
70 38 Kalispell 21 4
78 41 Libby 25 5
73 42 Missoula 23 6
70 32 Polebridge 21 0
71 46 Polson 22 8
70 41 Rogers Pass 21 5
73 37 Seeley Lake 23 3
68 41 West Glacier 20 5
69 40 Whitefish 20 5

Southwestern Montana

Average daily temperatures in September
High °F Low °F Place High °C Low °C
72 40 Anaconda 22 4
71 42 Bozeman 22 6
69 37 Butte 21 3
70 35 Deer Lodge 21 1
71 39 Dillon 22 4
76 44 Gardiner 24 7
68 37 Hebgen Lake Dam 20 3
73 45 Helena 23 7
73 34 Sula 23 1
71 41 Virginia City 22 5
68 30 West Yellowstone 20 -1

South - Central Montana

September temperatures: daily averages
High °F Low °F Place High °C Low °C
76 49 Bighorn Lake, Yellowtail Dam 25 9
74 49 Billings 24 9
62 31 Cooke City 17 0
66 42 Mystic Lake 19 5
71 42 Red Lodge 22 5

Eastern Montana

Average September temperatures
High °F Low °F Place High °C Low °C
76 44 Culbertson 24 6
74 43 Elwell Lake, Tiber Dam 23 6
77 48 Fort Peck Lake Dam 25 9
73 47 Glasgow 23 8
76 48 Glendive 25 9
72 43 Great Falls 22 6
73 43 Havre City 23 6
70 42 Lewistown 21 5
76 47 Miles City 24 8
Reference

NOAA National Centers for Environmental Information (NCEI). Climate Normals.

Montana Temperatures
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