September weather forecastLibby, MT
September
Weather in September
In Libby, Montana, September sings the melody of early fall with a drop in temperature compared to August. In contrast to the high temperature and prolonged sunshine hours of the earlier summer months, September experiences a gradual decline. A highlight of this month is the return of snowfall, measuring a slight 0.71" (18mm). The cloud cover also begins to increase, foreshadowing the colder months to come.Temperature
The onset of September in Libby is marked by a decrease in temperature, transitioning from a moderately hot 77.5°F (25.3°C) in August to an enjoyable 66°F (18.9°C). Despite a significant disparity with daytime temperatures, an average low-temperature of 39.7°F (4.3°C) is recorded in Libby during September.Humidity
The average relative humidity in September is 63%.Rainfall
In September, the rain falls for 8.5 days. Throughout September, 0.91" (23mm) of precipitation is accumulated. In Libby, during the entire year, the rain falls for 138.8 days and collects up to 18.15" (461mm) 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 0.4 snowfall days, it receives 0.71" (18mm) of snow. Throughout the year, in Libby, there are 91.8 snowfall days, and 49.33" (1253mm) of snow is accumulated.Daylight
In Libby, the average length of the day in September is 12h and 34min.On the first day of September in Libby, sunrise is at 7:00 am and sunset at 8:23 pm. On the last day of the month, sunrise is at 7:41 am and sunset at 7:22 pm MDT.
Sunshine
The average sunshine in September in Libby is 9h.UV index
In September, the average daily maximum UV index is 3. A UV Index estimate of 3 to 5 represents a medium vulnerability from unprotected exposure to Sun's UV rays for ordinary individuals.Note: The daily high UV index of 3 during September translates into the following recommendations:
Ensure safety - Sun damage prevention is strongly urged. It's recommended to limit sun exposure when its radiation is at its peak during midday. Sun-related eye harm can be minimized with proper sunglasses offering UVA and UVB coverage. Be on the lookout! Nearly twofold UV radiation from the Sun can be reflected by snow.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Libby, MT
- Average high temperature in September: 66°F
The warmest month (with the highest average high temperature) is August (77.5°F).
The month with the lowest average high temperature is December (27.1°F).
- Average low temperature in September: 39.7°F
The month with the highest average low temperature is August (47.3°F).
The coldest month (with the lowest average low temperature) is December (15.1°F).
Average pressure in September
Libby, MT
- Average pressure in September: 29.98"Hg
The month with the highest atmospheric pressure is January (30.18"Hg).
The month with the lowest atmospheric pressure is June (29.92"Hg).
Average wind speed in September
Libby, MT
- Average wind speed in September: 3.9mph
The windiest months (with the highest average wind speed) are April and June (4.5mph).
The calmest month (with the lowest average wind speed) is December (3.5mph).
Average humidity in September
Libby, MT
- Average humidity in September: 63%
The month with the highest relative humidity is January (94%).
The month with the lowest relative humidity is August (53%).
Average rainfall in September
Libby, MT
- Average rainfall in September: 0.91"
The wettest month (with the highest rainfall) is December (2.24").
The driest month (with the least rainfall) is August (0.43").
Average rainfall days in September
Libby, MT
- Average rainfall days in September: 8.5 days
The month with the highest number of rainy days is April (17.5 days).
The month with the least rainy days is August (5.9 days).
Average snowfall in September
Libby, MT
- Average snowfall in September: 0.71"
The month with the highest snowfall is January (11.34").
The months with the least snowfall are June, July and August (0").
Average snowfall days in September
Libby, MT
- Average snowfall days in September: 0.4 days
The month with the highest number of snowfall days is December (20 days).
The months with the least snowfall days are June, July and August (0 days).
Average daylight in September /
Average sunshine in September
Libby, MT
- Average daylight in September: 12h and 36min
The month with the longest days is June (Average daylight: 16h and 0min).
The month with the shortest days is December (Average daylight: 8h and 24min).
- Average sunshine in September: 9h and 0min
The months with the most sunshine are July and August (Average sunshine: 11h and 36min).
The month with the least sunshine is January (Average sunshine: 3h and 0min).
Average sunshine days in September
Libby, MT
- Average sunshine days in September: 19.5 days
The month with the most sunshine days is August (22.8 days).
The month with the least sunshine days is February (7.4 days).
Average UV index in September
Libby, MT
- Average UV index in September: 3
The months with the highest UV index are June and July (UV index 5).
The months with the lowest UV index are January, February, November and December (UV index 1).
Average cloud cover in September
Libby, MT
- Average cloud cover in September: 26
The month with the most cloud cover is January (Cloud cover 70).
The month with the least cloud cover is August (Cloud cover 15).
Average visibility in September
Libby, MT
- Average visibility in September: 6mi
The months with the highest visibility are May, June, July, August and September (6mi).
The month with the lowest visibility is January (2mi).
