Contents
- Weather in September
- Frequently asked questions
- Average temperature in September
- Average pressure in September
- Average wind speed in September
- Average humidity in September
- Average rainfall in September
- Average rainfall days in September
- Average snowfall in September
- Average snowfall days in September
- Average daylight in September
- Average sunshine in September
- Average sunshine days in September
- Average UV index in September
- Average cloud cover in September
- Average visibility in September
Weather in September
Temperature
Great Falls's September weather features a mild decline in high-temperatures, reducing from a moderately hot 81.9°F (27.7°C) in August to an agreeable 71.2°F (21.8°C). Great Falls experiences a consistent average temperature of 50.5°F (10.3°C) throughout the nights in September.Humidity
In September, the average relative humidity is 46%.Rainfall
In September, in Great Falls, the rain falls for 5.3 days. Throughout September, 0.31" (8mm) of precipitation is accumulated. In Great Falls, during the entire year, the rain falls for 68.2 days and collects up to 4.49" (114mm) of precipitation.Snowfall
January through May, September through December are months with snowfall in Great Falls. September is the first month it typically snows in Great Falls. Throughout September, in the average 0.5 snowfall days, it receives 0.79" (20mm) of snow. Throughout the year, there are 45.4 snowfall days, and 11.61" (295mm) of snow is accumulated.Daylight
In September, the average length of the day in Great Falls is 12h and 33min.On the first day of the month, sunrise is at 6:45 am and sunset at 8:04 pm. On the last day of September, in Great Falls, sunrise is at 7:23 am and sunset at 7:05 pm MDT.
Sunshine
In Great Falls, the average sunshine in September is 9.7h.UV index
In September, the average daily maximum UV index in Great Falls is 4. A UV Index of 3 to 5 symbolizes a moderate health risk from exposure to the Sun's UV rays for ordinary individuals.Note: The UV index of 4 during September translates into the following guidance:
Ensure safety - Recommendations to avert sunburn are presented. The mid-day Sun emits the most powerful UV radiation, so seek shade and minimize exposure. Sun protection is enhanced with clothing that boasts a tight weave yet offers a loose fit. Take note! UV radiation from the Sun can double in intensity due to snow reflection.
Frequently asked questions
What is the average September temperature in Great Falls?
What is the average humidity in September in Great Falls?
How many days does it rain in September in Great Falls?
When does it start to snow in Great Falls?
How many hours of daylight does Great Falls have in September?
What time are sunrise and sunset in September in Great Falls?
How long on average sun shines in September in Great Falls?
How high is the UV index in September in Great Falls?
Average temperature in September
Great Falls, MT
- Average high temperature in September: 71.2°F
The warmest month (with the highest average high temperature) is July (83.1°F).
The month with the lowest average high temperature is December (30°F).
- Average low temperature in September: 50.5°F
The month with the highest average low temperature is August (57.7°F).
The coldest months (with the lowest average low temperature) are February and December (18.3°F).
Average pressure in September
Great Falls, MT
- Average pressure in September: 29.95"Hg
The month with the highest atmospheric pressure is January (30.14"Hg).
The month with the lowest atmospheric pressure is June (29.87"Hg).
Average wind speed in September
Great Falls, MT
- Average wind speed in September: 8.6mph
The windiest month (with the highest average wind speed) is November (11.4mph).
The calmest month (with the lowest average wind speed) is August (7.7mph).
Average humidity in September
Great Falls, MT
- Average humidity in September: 46%
The month with the highest relative humidity is January (77%).
The month with the lowest relative humidity is August (40%).
Average rainfall in September
Great Falls, MT
- Average rainfall in September: 0.31"
The wettest month (with the highest rainfall) is June (0.87").
The driest month (with the least rainfall) is December (0.16").
Average rainfall days in September
Great Falls, MT
- Average rainfall days in September: 5.3 days
The month with the highest number of rainy days is April (9.9 days).
The month with the least rainy days is December (2.7 days).
Average snowfall in September
Great Falls, MT
- Average snowfall in September: 0.79"
The month with the highest snowfall is February (2.09").
The months with the least snowfall are June, July and August (0").
Average snowfall days in September
Great Falls, MT
- Average snowfall days in September: 0.5 days
The month with the highest number of snowfall days is February (10 days).
The months with the least snowfall days are June, July and August (0 days).
Average daylight in September /
Average sunshine in September
Great Falls, MT
- Average daylight in September: 12h and 3min
The month with the longest days is June (Average daylight: 15h and 54min).
The month with the shortest days is December (Average daylight: 8h and 30min).
- Average sunshine in September: 9h and 4min
The month with the most sunshine is July (Average sunshine: 12h and 6min).
The months with the least sunshine are January, February and December (Average sunshine: 5h and 30min).
Average sunshine days in September
Great Falls, MT
- Average sunshine days in September: 23.6 days
The month with the most sunshine days is July (26.1 days).
The months with the least sunshine days are February and April (16.2 days).
Average UV index in September
Great Falls, MT
- Average UV index in September: 4
The month with the highest UV index is July (UV index 6).
The months with the lowest UV index are January, February, March, October, November and December (UV index 2).
Average cloud cover in September
Great Falls, MT
- Average cloud cover in September: 23
The month with the most cloud cover is February (Cloud cover 46).
The month with the least cloud cover is July (Cloud cover 13).
Average visibility in September
Great Falls, MT
- Average visibility in September: 6mi
The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
Great Falls, Montana, USA
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