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
September ushers in a slight temperature change, with average high-temperatures reducing from August's moderately hot 76.5°F (24.7°C) to an enjoyable 66.2°F (19°C). Rollins registers a marked temperature plunge to a wintry 41.9°F (5.5°C) during the cool September nights.Humidity
The average relative humidity in September is 61%.Rainfall
In Rollins, in September, it is raining for 10.5 days, with typically 1.1" (28mm) of accumulated precipitation. Throughout the year, there are 153.5 rainfall days, and 19.76" (502mm) of precipitation is accumulated.Snowfall
Months with snowfall are January through May, September through December. September is the first month it typically snows. Throughout September, in the average 0.2 snowfall days, it receives 0.31" (8mm) of snow. Throughout the year, there are 94.5 snowfall days, and 52.6" (1336mm) of snow is accumulated.Daylight
The average length of the day in September is 12h and 33min.On the first day of the month, sunrise is at 6:56 am and sunset at 8:16 pm. On the last day of September, sunrise is at 7:35 am and sunset at 7:17 pm MDT.
Sunshine
The average sunshine in September is 9.3h.UV index
In September, the average daily maximum UV index is 3. A UV Index of 3 to 5 symbolizes a medium vulnerability from exposure to the Sun's UV rays for the average person.Note: The maximum UV index, 3 during September, leads to the following recommendations:
Undertake precautions - Guarding against sun damage is counselled. The Sun's radiation is especially intense around midday; try to stay in shade during this period. To cut down UV radiation exposure by about half, sport a wide-brim hat. Be aware! The reflective nature of snow can magnify the Sun's UV radiation almost twofold.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What are September temperatures?
What is the average humidity in September in Rollins?
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 long on average sun shines in September?
What is the UV index intensity in September?
Average temperature in September
Rollins, MT
- Average high temperature in September: 66.2°F
The warmest month (with the highest average high temperature) is July (76.6°F).
The month with the lowest average high temperature is December (27.5°F).
- Average low temperature in September: 41.9°F
The month with the highest average low temperature is July (48.7°F).
The coldest month (with the lowest average low temperature) is December (16.7°F).
Average pressure in September
Rollins, MT
- Average pressure in September: 29.98"Hg
The month with the highest atmospheric pressure is January (30.17"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).
Average wind speed in September
Rollins, MT
- Average wind speed in September: 4mph
The windiest month (with the highest average wind speed) is April (4.9mph).
The calmest month (with the lowest average wind speed) is August (3.8mph).
Average humidity in September
Rollins, MT
- Average humidity in September: 61%
The month with the highest relative humidity is January (91%).
The month with the lowest relative humidity is August (53%).
Average rainfall in September
Rollins, MT
- Average rainfall in September: 1.1"
The wettest month (with the highest rainfall) is June (2.36").
The driest months (with the least rainfall) are July and August (0.63").
Average rainfall days in September
Rollins, MT
- Average rainfall days in September: 10.5 days
The month with the highest number of rainy days is April (18.8 days).
The month with the least rainy days is August (7.2 days).
Average snowfall in September
Rollins, MT
- Average snowfall in September: 0.31"
The month with the highest snowfall is December (12.32").
The months with the least snowfall are June, July and August (0").
Average snowfall days in September
Rollins, MT
- Average snowfall days in September: 0.2 days
The month with the highest number of snowfall days is December (20.1 days).
The months with the least snowfall days are June, July and August (0 days).
Average daylight in September /
Average sunshine in September
Rollins, MT
- Average daylight in September: 12h and 4min
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 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 6min).
Average sunshine days in September
Rollins, MT
- Average sunshine days in September: 17.4 days
The month with the most sunshine days is July (20.2 days).
The months with the least sunshine days are February and March (7.8 days).
Average UV index in September
Rollins, 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, November and December (UV index 1).
Average cloud cover in September
Rollins, MT
- Average cloud cover in September: 23
The month with the most cloud cover is January (Cloud cover 59).
The months with the least cloud cover are July and August (Cloud cover 15).
Average visibility in September
Rollins, 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, March and December (4mi).
Rollins, Montana, USA
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