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 onset of September brings a small change in high-temperatures, falling from a warm 79.3°F (26.3°C) in August to an agreeable 68.5°F (20.3°C). The nighttime temperature during September exhibits a clear drop from daytime highs, settling at a cold 42.3°F (5.7°C).Humidity
In Perma, the average relative humidity in September is 58%.Rainfall
In Perma, during September, the rain falls for 9.3 days and regularly aggregates up to 0.91" (23mm) of precipitation. In Perma, during the entire year, the rain falls for 129.9 days and collects up to 13.5" (343mm) of precipitation.Snowfall
January through May, September through December are months with snowfall. September is the first month it typically snows in Perma. Throughout September, in the average 0.2 snowfall days, it receives 0.47" (12mm) of snow. In Perma, during the entire year, snow falls for 67.1 days and aggregates up to 28.27" (718mm) of snow.Daylight
In Perma, the average length of the day in September is 12h and 32min.On the first day of September, sunrise is at 6:58 am and sunset at 8:17 pm. On the last day of the month, sunrise is at 7:37 am and sunset at 7:19 pm MDT.
Sunshine
In Perma, the average sunshine in September is 9.3h.UV index
In Perma, Montana, the average daily maximum UV index in September is 3. A UV Index value of 3 to 5 symbolizes a moderate threat to health from unprotected exposure to Sun's UV rays for average individuals.Note: The UV index of 3 during September translates into the following guidance:
Undertake protective steps - Preventing sun damage is advised. Midday Sun has the strongest UV rays, making it crucial to limit exposure and find shade. A hat with a broad brim is indispensable, filtering out up to half of UV rays. Note this! The Sun's UV radiation can nearly be doubled by the reflection off snow.
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Data Sources | Weather Forecasting & Climate
Frequently asked questions
What are September temperatures in Perma?
What is the average humidity in September in Perma?
How much does it rain in Perma in September?
When does it start to snow in Perma?
How many hours of daylight does Perma have in September?
When is the sunrise / sunset in September in Perma?
How long on average sun shines in September in Perma?
What is the UV index reading in September in Perma?
Average temperature in September
Perma, MT
- Average high temperature in September: 68.5°F
The warmest month (with the highest average high temperature) is July (79.7°F).
The month with the lowest average high temperature is December (28.4°F).
- Average low temperature in September: 42.3°F
The month with the highest average low temperature is August (49.5°F).
The coldest month (with the lowest average low temperature) is December (16.7°F).
Average pressure in September
Perma, 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
Perma, MT
- Average wind speed in September: 4mph
The windiest month (with the highest average wind speed) is April (4.8mph).
The calmest months (with the lowest average wind speed) are January, August and December (3.9mph).
Average humidity in September
Perma, MT
- Average humidity in September: 58%
The month with the highest relative humidity is January (91%).
The month with the lowest relative humidity is August (49%).
Average rainfall in September
Perma, MT
- Average rainfall in September: 0.91"
The wettest month (with the highest rainfall) is June (2.2").
The driest months (with the least rainfall) are July and August (0.63").
Average rainfall days in September
Perma, MT
- Average rainfall days in September: 9.3 days
The month with the highest number of rainy days is June (15.7 days).
The month with the least rainy days is August (7.4 days).
Average snowfall in September
Perma, MT
- Average snowfall in September: 0.47"
The month with the highest snowfall is February (6.5").
The months with the least snowfall are June, July and August (0").
Average snowfall days in September
Perma, MT
- Average snowfall days in September: 0.2 days
The month with the highest number of snowfall days is December (14.5 days).
The months with the least snowfall days are June, July and August (0 days).
Average daylight in September /
Average sunshine in September
Perma, 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 2min
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 42min).
Average sunshine days in September
Perma, MT
- Average sunshine days in September: 18.2 days
The month with the most sunshine days is July (20.8 days).
The month with the least sunshine days is February (11 days).
Average UV index in September
Perma, 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
Perma, MT
- Average cloud cover in September: 23
The month with the most cloud cover is February (Cloud cover 52).
The month with the least cloud cover is August (Cloud cover 14).
Average visibility in September
Perma, MT
- Average visibility in September: 6mi
The months with the highest visibility are April, May, June, July, August, September and October (6mi).
The months with the lowest visibility are January, February and December (4mi).
Perma, Montana, USA
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