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
The beginning of September marks a decrease in the average high-temperature, transitioning from an agreeable 72.7°F (22.6°C) in August to a comfortable 63.5°F (17.5°C). A steady average of 39.6°F (4.2°C) throughout September underscores a considerable divergence from the daytime high.Humidity
In September, the average relative humidity is 57%.Rainfall
In Big Sky, in September, during 11.1 rainfall days, 1.81" (46mm) of precipitation is typically accumulated. Throughout the year, there are 116.1 rainfall days, and 23.5" (597mm) of precipitation is accumulated.Snowfall
Months with snowfall are January through December. In September, it is snowing for 3.6 days. Throughout September, 5.04" (128mm) of snow is accumulated. Throughout the year, in Big Sky, there are 151.6 snowfall days, and 124.06" (3151mm) of snow is accumulated.Daylight
In September, the average length of the day is 12h and 31min.On the first day of September, sunrise is at 6:47 am and sunset at 8:01 pm. On the last day of the month, sunrise is at 7:23 am and sunset at 7:06 pm MDT.
Sunshine
In Big Sky, the average sunshine in September is 9.8h.UV index
In September, the average daily maximum UV index is 3. A UV Index value of 3 to 5 symbolizes a moderate threat to health from exposure to the Sun's UV radiation for ordinary individuals.Note: In September, a daily maximum UV index of 3 leads to the following instructions:
Be careful. Light complexion individuals might get burns in fewer than 30 minutes. Direct exposure to the Sun's intense radiation around midday should be avoided for health reasons. On bright days sunglasses that block both UVA and UVB rays should be worn. A hat with a wide brim is extremely helpful, as it can prevent roughly 50% of UV radiation from reaching the eyes. Be watchful! The reflection of snow can enhance the intensity of the Sun's UV radiation nearly double.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What is the usual temperature for Big Sky in September?
What is the average humidity in September?
How many days does it rain in September?
How many days does it snow in September?
How many hours of daylight does Big Sky have in September?
When is the sunrise / sunset in September?
How long on average sun shines in September?
What is the UV index reading in September?
Average temperature in September
Big Sky, MT
- Average high temperature in September: 63.5°F
The warmest month (with the highest average high temperature) is July (74.8°F).
The month with the lowest average high temperature is December (22.5°F).
- Average low temperature in September: 39.6°F
The month with the highest average low temperature is August (45.1°F).
The coldest month (with the lowest average low temperature) is December (7.9°F).
Average pressure in September
Big Sky, MT
- Average pressure in September: 29.99"Hg
The month with the highest atmospheric pressure is January (30.22"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).
Average wind speed in September
Big Sky, MT
- Average wind speed in September: 5.2mph
The windiest month (with the highest average wind speed) is January (7.1mph).
The calmest month (with the lowest average wind speed) is August (4.8mph).
Average humidity in September
Big Sky, MT
- Average humidity in September: 57%
The months with the highest relative humidity are January and February (90%).
The month with the lowest relative humidity is August (51%).
Average rainfall in September
Big Sky, MT
- Average rainfall in September: 1.81"
The wettest months (with the highest rainfall) are April and May (2.91").
The driest month (with the least rainfall) is July (1.18").
Average rainfall days in September
Big Sky, MT
- Average rainfall days in September: 11.1 days
The month with the highest number of rainy days is June (16.6 days).
The month with the least rainy days is February (4.3 days).
Average snowfall in September
Big Sky, MT
- Average snowfall in September: 5.04"
The month with the highest snowfall is April (19.88").
The month with the least snowfall is August (0.08").
Average snowfall days in September
Big Sky, MT
- Average snowfall days in September: 3.6 days
The month with the highest number of snowfall days is March (21 days).
The month with the least snowfall days is August (0.3 days).
Average daylight in September /
Average sunshine in September
Big Sky, MT
- Average daylight in September: 12h and 3min
The month with the longest days is June (Average daylight: 15h and 36min).
The month with the shortest days is December (Average daylight: 8h and 48min).
- Average sunshine in September: 9h and 5min
The month with the most sunshine is July (Average sunshine: 11h and 42min).
The month with the least sunshine is January (Average sunshine: 4h and 42min).
Average sunshine days in September
Big Sky, MT
- Average sunshine days in September: 14.5 days
The month with the most sunshine days is September (14.5 days).
The month with the least sunshine days is May (5.7 days).
Average UV index in September
Big Sky, MT
- Average UV index in September: 3
The month with the highest UV index is July (UV index 5).
The months with the lowest UV index are January and February (UV index 1).
Average cloud cover in September
Big Sky, MT
- Average cloud cover in September: 23
The month with the most cloud cover is February (Cloud cover 60).
The month with the least cloud cover is July (Cloud cover 17).
Average visibility in September
Big Sky, MT
- Average visibility in September: 6mi
The months with the highest visibility are June, July, August, September and October (6mi).
The months with the lowest visibility are January, February, March, April and December (4mi).
Big Sky, Montana, USA
Weather forecast for your location
2. Allow the app to use your location