September weather forecastMissoula, MT
September
Weather in September
The month of September in Missoula heralds the arrival of autumn, as temperatures dalliance towards lower measurements. Relative to October, September's weather is considerably warmer with lower humidity and rainfall levels. While maintaining lengthier daylight hours, the month also records slightly higher sunshine hours and days. The shift from summer is marked by the return of rainfall and a slight drop in temperatures. Temperatures in September range from 41°F (5°C) to 68.7°F (20.4°C) — a noticeable cooldown from the high summer temperatures.Temperature
September's onset in Missoula, Montana, corresponds with a shift in the average high-temperature, moving from a warm 79.7°F (26.5°C) in August to a pleasant 68.7°F (20.4°C). Missoula in September observes a sharp transition from the daytime heat, falling to an average low of 41°F (5°C).Humidity
The average relative humidity in September in Missoula is 58%.Rainfall
In Missoula, during September, the rain falls for 4.2 days and regularly aggregates up to 0.24" (6mm) of precipitation. In Missoula, during the entire year, the rain falls for 67.5 days and collects up to 3.27" (83mm) of precipitation.Snowfall
Months with snowfall in Missoula are January through May, September through December. September is the first month it typically snows. Throughout September, in the average 0.1 snowfall days, it receives 0.2" (5mm) of snow. Throughout the year, there are 44 snowfall days, and 8.07" (205mm) of snow is accumulated.Daylight
In September, the average length of the day in Missoula is 12h and 32min.On the first day of September, sunrise is at 6:56 am and sunset at 8:14 pm. On the last day of the month, sunrise is at 7:34 am and sunset at 7:16 pm MDT.
Sunshine
In Missoula, the average sunshine in September is 9.4h.UV index
In September, the average daily maximum UV index is 3. A UV Index of 3 to 5 symbolizes a moderate threat to health from exposure to the Sun's UV rays for the ordinary person.Note: The daily maximum UV index of 3 in September interprets into the following advice:
Take precautions - Protection against sun damage is advised. To guard against the harmful effects of the Sun, minimize exposure during midday. Always opt for UVA and UVB-resistant sunglasses on radiant days. Observe! Snow reflection can nearly intensify the Sun's UV radiation twofold.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Missoula, MT
- Average high temperature in September: 68.7°F
The warmest month (with the highest average high temperature) is July (80.2°F).
The month with the lowest average high temperature is December (28°F).
- Average low temperature in September: 41°F
The month with the highest average low temperature is August (46.9°F).
The coldest month (with the lowest average low temperature) is December (15.4°F).
Average pressure in September
Missoula, MT
- Average pressure in September: 29.98"Hg
The month with the highest atmospheric pressure is January (30.19"Hg).
The month with the lowest atmospheric pressure is June (29.93"Hg).
Average wind speed in September
Missoula, MT
- Average wind speed in September: 4.2mph
The windiest month (with the highest average wind speed) is April (5mph).
The calmest month (with the lowest average wind speed) is August (4mph).
Average humidity in September
Missoula, MT
- Average humidity in September: 58%
The month with the highest relative humidity is January (90%).
The month with the lowest relative humidity is July (50%).
Average rainfall in September
Missoula, MT
- Average rainfall in September: 0.24"
The wettest month (with the highest rainfall) is April (0.47").
The driest months (with the least rainfall) are July and December (0.16").
Average rainfall days in September
Missoula, MT
- Average rainfall days in September: 4.2 days
The month with the highest number of rainy days is April (8.8 days).
The month with the least rainy days is August (3.3 days).
Average snowfall in September
Missoula, MT
- Average snowfall in September: 0.2"
The month with the highest snowfall is February (2.36").
The months with the least snowfall are June, July and August (0").
Average snowfall days in September
Missoula, MT
- Average snowfall days in September: 0.1 days
The month with the highest number of snowfall days is December (9 days).
The months with the least snowfall days are June, July and August (0 days).
Average daylight in September /
Average sunshine in September
Missoula, MT
- Average daylight in September: 12h and 30min
The month with the longest days is June (Average daylight: 15h and 48min).
The month with the shortest days is December (Average daylight: 8h and 36min).
- Average sunshine in September: 9h and 24min
The month with the most sunshine is July (Average sunshine: 11h and 48min).
The month with the least sunshine is January (Average sunshine: 4h and 54min).
Average sunshine days in September
Missoula, MT
- Average sunshine days in September: 24.5 days
The month with the most sunshine days is July (27 days).
The month with the least sunshine days is April (17.8 days).
Average UV index in September
Missoula, MT
- Average UV index in September: 3
The month with the highest UV index is July (UV index 6).
The months with the lowest UV index are February and December (UV index 1).
Average cloud cover in September
Missoula, MT
- Average cloud cover in September: 23
The month with the most cloud cover is February (Cloud cover 54).
The month with the least cloud cover is July (Cloud cover 14).
Average visibility in September
Missoula, 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 and December (4mi).
