September weather forecastSaint Johns, MT
September
Weather in September
The first month of the autumn, September, is still a pleasant month in Saint Johns, Montana, with an average temperature varying between 52.5°F (11.4°C) and 70.5°F (21.4°C).Temperature
The onset of September results in a decrease in the average high-temperature, receding from a warm 81.3°F (27.4°C) in August to a pleasant 70.5°F (21.4°C). Saint Johns's average low-temperature during September nights is observed to be a cool 52.5°F (11.4°C).Humidity
The average relative humidity in September is 45%.Rainfall
In Saint Johns, during September, the rain falls for 7.6 days and regularly aggregates up to 0.63" (16mm) of precipitation. In Saint Johns, during the entire year, the rain falls for 98.7 days and collects up to 8.23" (209mm) 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 0.2 snowfall days, it receives 0.51" (13mm) of snow. In Saint Johns, during the entire year, snow falls for 53.5 days and aggregates up to 14.25" (362mm) of snow.Daylight
In Saint Johns, the average length of the day in September is 12h and 34min.On the first day of the month, sunrise is at 6:38 am and sunset at 8:01 pm. On the last day of September, sunrise is at 7:19 am and sunset at 7:00 pm MDT.
Sunshine
In September, the average sunshine is 10.1h.UV index
In Saint Johns, Montana, the average daily maximum UV index in September is 4. A UV Index estimate of 3 to 5 represents a moderate health risk from exposure to the Sun's UV rays for ordinary individuals.Note: In September, a regular UV index of 4 translates into these guidelines:
Guard yourself - Avoiding sunburn is suggested. Sun exposure should be minimized, especially during midday, to avoid harmful UV radiation. On bright days sunglasses that block both UVA and UVB rays should be worn. A hat with a wide brim is extremely helpful, as it can prevent roughly 50% of UV radiation from reaching the eyes. Take into account! The reflection from snow can nearly double the Sun's UV radiation intensity.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Saint Johns, MT
- Average high temperature in September: 70.5°F
The warmest month (with the highest average high temperature) is July (82.8°F).
The months with the lowest average high temperature are January and December (27.1°F).
- Average low temperature in September: 52.5°F
The month with the highest average low temperature is August (61.3°F).
The coldest month (with the lowest average low temperature) is February (13.5°F).
Average pressure in September
Saint Johns, MT
- Average pressure in September: 29.93"Hg
The months with the highest atmospheric pressure are January and February (30.12"Hg).
The month with the lowest atmospheric pressure is June (29.84"Hg).
Average wind speed in September
Saint Johns, MT
- Average wind speed in September: 9mph
The windiest month (with the highest average wind speed) is April (10.6mph).
The calmest month (with the lowest average wind speed) is August (8.5mph).
Average humidity in September
Saint Johns, MT
- Average humidity in September: 45%
The month with the highest relative humidity is January (83%).
The month with the lowest relative humidity is August (40%).
Average rainfall in September
Saint Johns, MT
- Average rainfall in September: 0.63"
The wettest month (with the highest rainfall) is June (1.5").
The driest month (with the least rainfall) is December (0.31").
Average rainfall days in September
Saint Johns, MT
- Average rainfall days in September: 7.6 days
The month with the highest number of rainy days is May (13.8 days).
The month with the least rainy days is February (4 days).
Average snowfall in September
Saint Johns, MT
- Average snowfall in September: 0.51"
The month with the highest snowfall is February (2.72").
The months with the least snowfall are June, July and August (0").
Average snowfall days in September
Saint Johns, MT
- Average snowfall days in September: 0.2 days
The month with the highest number of snowfall days is February (11 days).
The months with the least snowfall days are June, July and August (0 days).
Average daylight in September /
Average sunshine in September
Saint Johns, MT
- Average daylight in September: 12h and 36min
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: 10h and 6min
The month with the most sunshine is July (Average sunshine: 12h and 0min).
The month with the least sunshine is February (Average sunshine: 5h and 18min).
Average sunshine days in September
Saint Johns, MT
- Average sunshine days in September: 20.3 days
The month with the most sunshine days is September (20.3 days).
The month with the least sunshine days is April (12.8 days).
Average UV index in September
Saint Johns, 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
Saint Johns, MT
- Average cloud cover in September: 22
The month with the most cloud cover is February (Cloud cover 46).
The months with the least cloud cover are July and August (Cloud cover 16).
Average visibility in September
Saint Johns, 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).
