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
September
Weather in September
Temperature
A decrease in the average high-temperature is observed during September, shifting from a moderately hot 74.7°F (23.7°C) in August to a refreshing 65.3°F (18.5°C). Despite substantial daily fluctuations, the average low-temperature is a wintry 40.6°F (4.8°C) during September.Humidity
In Jackson, the average relative humidity in September is 50%.Rainfall
In Jackson, in September, it is raining for 9.4 days, with typically 0.94" (24mm) of accumulated precipitation. In Jackson, during the entire year, the rain falls for 129.5 days and collects up to 12.4" (315mm) of precipitation.Snowfall
January through May, September through December are months with snowfall. September is the first month it typically snows. Throughout September, in the average 0.3 snowfall days, it receives 0.43" (11mm) of snow. Throughout the year, there are 63.5 snowfall days, and 22.76" (578mm) of snow is accumulated.Daylight
The average length of the day in September is 12h and 31min.On the first day of the month, sunrise is at 6:56 am and sunset at 8:10 pm. On the last day of September, sunrise is at 7:31 am and sunset at 7:15 pm MDT.
Sunshine
In Jackson, the average sunshine in September is 9.4h.UV index
In September, the average daily maximum UV index is 3. A UV Index reading of 3 to 5 represents a medium health hazard from exposure to the Sun's UV radiation for average individuals.Note: The UV index of 3 during September translates into the following guidance:
Exercise prevention - Precautions against solar damage are endorsed. The Sun's most intense and consequently most harmful UV radiation during midday hours should be decreased by minimizing exposure and seeking shade. Tightly woven clothing, when worn loosely, shields effectively against the Sun. Be informed! The Sun's UV radiation can be nearly doubled due to the reflection from snow.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What is the average September temperature?
What is the average humidity in September?
How much does it rain in September?
When does it start to snow?
What is the average length of the day in September?
When is the sunrise / sunset in September?
How many hours of sunshine does Jackson have in September?
What is the UV index reading in September?
Average temperature in September
Jackson, MT
- Average high temperature in September: 65.3°F
The warmest month (with the highest average high temperature) is July (75.7°F).
The month with the lowest average high temperature is December (25.2°F).
- Average low temperature in September: 40.6°F
The month with the highest average low temperature is August (47.5°F).
The coldest months (with the lowest average low temperature) are January and December (9.5°F).
Average pressure in September
Jackson, MT
- Average pressure in September: 29.99"Hg
The month with the highest atmospheric pressure is January (30.25"Hg).
The month with the lowest atmospheric pressure is June (29.93"Hg).
Average wind speed in September
Jackson, MT
- Average wind speed in September: 4.5mph
The windiest months (with the highest average wind speed) are March and April (5.2mph).
The calmest month (with the lowest average wind speed) is August (4.3mph).
Average humidity in September
Jackson, MT
- Average humidity in September: 50%
The month with the highest relative humidity is February (89%).
The month with the lowest relative humidity is August (43%).
Average rainfall in September
Jackson, MT
- Average rainfall in September: 0.94"
The wettest month (with the highest rainfall) is June (2.05").
The driest months (with the least rainfall) are July and August (0.51").
Average rainfall days in September
Jackson, MT
- Average rainfall days in September: 9.4 days
The month with the highest number of rainy days is May (18.3 days).
The month with the least rainy days is January (6.3 days).
Average snowfall in September
Jackson, MT
- Average snowfall in September: 0.43"
The month with the highest snowfall is February (5").
The months with the least snowfall are June, July and August (0").
Average snowfall days in September
Jackson, MT
- Average snowfall days in September: 0.3 days
The month with the highest number of snowfall days is February (12.3 days).
The months with the least snowfall days are June, July and August (0 days).
Average daylight in September /
Average sunshine in September
Jackson, 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 2min
The month with the most sunshine is July (Average sunshine: 11h and 48min).
The month with the least sunshine is January (Average sunshine: 5h and 6min).
Average sunshine days in September
Jackson, MT
- Average sunshine days in September: 17.7 days
The month with the most sunshine days is July (19.4 days).
The month with the least sunshine days is April (7.7 days).
Average UV index in September
Jackson, 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, February and December (UV index 1).
Average cloud cover in September
Jackson, MT
- Average cloud cover in September: 19
The month with the most cloud cover is February (Cloud cover 53).
The month with the least cloud cover is August (Cloud cover 13).
Average visibility in September
Jackson, MT
- Average visibility in September: 6mi
The months with the highest visibility are May, June, July, August, September and October (6mi).
The months with the lowest visibility are January, February, March and December (4mi).