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
In Sweet Grass, the beginning of September is marked by a lowered average high-temperature, shifting from August's moderately hot 78.1°F (25.6°C) to a refreshing 67.6°F (19.8°C). Sweet Grass experiences an average low-temperature of 48.4°F (9.1°C) in the month of September.Humidity
The average relative humidity in September is 49%.Rainfall
In Sweet Grass, in September, it is raining for 6.2 days, with typically 0.71" (18mm) of accumulated precipitation. In Sweet Grass, during the entire year, the rain falls for 70.4 days and collects up to 8.46" (215mm) of precipitation.Snowfall
Months with snowfall in Sweet Grass are January through May, September through December. September is the first month it typically snows. Throughout September, in the average 0.8 snowfall days, it receives 0.51" (13mm) of snow. Throughout the year, there are 54.3 snowfall days, and 19.49" (495mm) of snow is accumulated.Daylight
In Sweet Grass, the average length of the day in September is 12h and 34min.On the first day of September, sunrise is at 6:45 am and sunset at 8:09 pm. On the last day of the month, sunrise is at 7:27 am and sunset at 7:07 pm MDT.
Sunshine
The average sunshine in September is 9.6h.UV index
In Sweet Grass, Montana, the average daily maximum UV index in September is 4. A UV Index value of 3 to 5 symbolizes a moderate threat to health from unsafe exposure to UV radiation for ordinary individuals.Note: In September, the UV index of 4 transforms into the following advice:
Be vigilant - A duty to shield skin and eyes from injury exists. Direct Sun exposure should be minimized especially during midday when radiation is most intense. Sunglasses providing both UVA and UVB protection are non-negotiable on sunlit days. Warning! The reflection from snow can nearly magnify the Sun's UV radiation twofold.
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 many days 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?
How high is the UV index in September?
Average temperature in September
Sweet Grass, MT
- Average high temperature in September: 67.6°F
The warmest month (with the highest average high temperature) is July (78.8°F).
The month with the lowest average high temperature is December (27.1°F).
- Average low temperature in September: 48.4°F
The month with the highest average low temperature is August (55.2°F).
The coldest month (with the lowest average low temperature) is December (15.3°F).
Average pressure in September
Sweet Grass, MT
- Average pressure in September: 29.95"Hg
The month with the highest atmospheric pressure is January (30.13"Hg).
The month with the lowest atmospheric pressure is June (29.87"Hg).
Average wind speed in September
Sweet Grass, MT
- Average wind speed in September: 9.5mph
The windiest month (with the highest average wind speed) is January (11.8mph).
The calmest months (with the lowest average wind speed) are July and August (8.8mph).
Average humidity in September
Sweet Grass, MT
- Average humidity in September: 49%
The month with the highest relative humidity is January (79%).
The month with the lowest relative humidity is August (43%).
Average rainfall in September
Sweet Grass, MT
- Average rainfall in September: 0.71"
The wettest month (with the highest rainfall) is June (1.77").
The driest month (with the least rainfall) is July (0.31").
Average rainfall days in September
Sweet Grass, MT
- Average rainfall days in September: 6.2 days
The month with the highest number of rainy days is May (10.4 days).
The month with the least rainy days is November (2.6 days).
Average snowfall in September
Sweet Grass, MT
- Average snowfall in September: 0.51"
The month with the highest snowfall is February (3.58").
The months with the least snowfall are June, July and August (0").
Average snowfall days in September
Sweet Grass, MT
- Average snowfall days in September: 0.8 days
The month with the highest number of snowfall days is December (10.2 days).
The months with the least snowfall days are July and August (0 days).
Average daylight in September /
Average sunshine in September
Sweet Grass, MT
- Average daylight in September: 12h and 4min
The month with the longest days is June (Average daylight: 16h and 6min).
The month with the shortest days is December (Average daylight: 8h and 18min).
- Average sunshine in September: 9h and 4min
The month with the most sunshine is July (Average sunshine: 12h and 0min).
The months with the least sunshine are January and December (Average sunshine: 5h and 36min).
Average sunshine days in September
Sweet Grass, MT
- Average sunshine days in September: 22.4 days
The month with the most sunshine days is July (23.5 days).
The month with the least sunshine days is April (17.4 days).
Average UV index in September
Sweet Grass, MT
- Average UV index in September: 4
The month with the highest UV index is July (UV index 6).
The months with the lowest UV index are January, February, March, October, November and December (UV index 2).
Average cloud cover in September
Sweet Grass, MT
- Average cloud cover in September: 23
The month with the most cloud cover is February (Cloud cover 43).
The month with the least cloud cover is July (Cloud cover 15).
Average visibility in September
Sweet Grass, MT
- Average visibility in September: 6mi
The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
Sweet Grass, Montana, USA
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