World Resorts USA Great Falls Weather

Great Falls weather in September

Weather in Great Falls: September

Average day temperature: 74.4°F
Average night temperature: 53.4°F
Number of sunny days: 21 days
Day length: 11.7 - 13.3 hours
Number of rainy days: 1 day
Precipitation totals: 0.7 in.

Air temperature in September, °F

Show year:
2025
2024
2023

The highest day temperature during September of 2025 was 86°F. At the same time the lowest night temperature was 42°F. Daily and nightly averages during September were 77.1°F and 51.7°F.

Sunny, partly cloudy and cloudy days

Mostly all days in September are sunny but cloudy days are also possible.

Precipitation total in September, in.

Precipitation total value in Great Falls in September is 0.7 in. Other months of the year show relatively similar values.

Wind speed in September, mph

The average wind speed value in September is 7.6 mph It makes September one of the least windy months of the year.

Average sunny hours

This chart shows average number of hours during the day when sunlight can reach the ground. It depends on day length and cloudiness during the day. The average number of sunny hours in September is: 9.5.

Best time for vacation in Great Falls

Sunniest months:
July 22 days
August 21 days
September 21 days
Warmest months:
July 83.9 °F
August 81.7 °F
September 74.4 °F
Coldest months:
February 28.7 °F
January 30.3 °F
December 33.0 °F
Rainiest months:
May 3 days
June 2 days
September 1 day
Windiest months:
November 9.7 mph
February 9.3 mph
January 9.0 mph

Great Falls on a weather map

Great Falls
+39°F
NE 4 mph
Feels like: +32°F
Precip.: 0%
Places in USA:
Name
°F
+30°F
+77°F
+77°F
+45°F
+55°F
+70°F
+77°F
+70°F
+25°F
+57°F
+48°F
+63°F
+63°F
+46°F
+9°F
24 Hours Forecast
Great Falls
Local time: 21:12
December 05, friday
0000
37°F
E
2 mph
0300
36°F
NE
6 mph
0600
30°F
NE
3 mph
0900
23°F
N
3 mph
1200
30°F
NE
3 mph
1500
36°F
E
2 mph
1800
32°F
W
2 mph
2100
32°F
S
1 mph
Units of measurement: °C / °F