September weather forecastHelmville, MT
September
Weather in September
The first month of the autumn, September, is also an enjoyable month in Helmville, Montana, with an average temperature ranging between min 40.3°F (4.6°C) and max 66.4°F (19.1°C).Temperature
In September, the meteorological conditions alter, with the average high-temperature shifting from a warm 77°F (25°C) in August to a refreshing 66.4°F (19.1°C). During September nights, Helmville documents a marked contrast from daily highs, with an average temperature of 40.3°F (4.6°C).Humidity
In September, the average relative humidity in Helmville is 56%.Rainfall
The months with the least rainfall in Helmville are August through October Rain falls for 6.9 days and accumulates 0.59" (15mm) of rain.Snowfall
January through June, September through December are months with snowfall. September is the first month it typically snows. Throughout September, in the average 0.5 snowfall days, it receives 0.39" (10mm) of snow. Throughout the year, in Helmville, there are 86.9 snowfall days, and 39.96" (1015mm) of snow is accumulated.Daylight
In Helmville, the average length of the day in September is 12h and 32min.On the first day of September, sunrise is at 6:52 am and sunset at 8:10 pm. On the last day of the month, sunrise is at 7:30 am and sunset at 7:12 pm MDT.
Sunshine
The average sunshine in September is 9.8h.UV index
In September, the average daily maximum UV index in Helmville, Montana, is 3. A UV Index estimate of 3 to 5 represents a medium health hazard from exposure to the Sun's UV rays for the average person.Note: The UV index of 3 during September translates into the following guidance:
Guard yourself - Avoiding sunburn is suggested. The mid-day Sun emits the most powerful UV radiation, so seek shade and minimize exposure. Employ a hat with a wide brim for robust protection, cutting UV exposure by half. On your guard! Snow's reflection can almost double the intensity of the Sun's UV radiation.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Helmville, MT
- Average high temperature in September: 66.4°F
The warmest month (with the highest average high temperature) is July (78.1°F).
The month with the lowest average high temperature is December (26.6°F).
- Average low temperature in September: 40.3°F
The month with the highest average low temperature is August (46.6°F).
The coldest month (with the lowest average low temperature) is December (12.6°F).
Average pressure in September
Helmville, MT
- Average pressure in September: 29.98"Hg
The month with the highest atmospheric pressure is January (30.19"Hg).
The month with the lowest atmospheric pressure is June (29.92"Hg).
Average wind speed in September
Helmville, MT
- Average wind speed in September: 5.2mph
The windiest month (with the highest average wind speed) is April (6mph).
The calmest month (with the lowest average wind speed) is August (4.7mph).
Average humidity in September
Helmville, MT
- Average humidity in September: 56%
The months with the highest relative humidity are January and February (89%).
The months with the lowest relative humidity are July and August (49%).
Average rainfall in September
Helmville, MT
- Average rainfall in September: 0.59"
The wettest month (with the highest rainfall) is June (1.81").
The driest months (with the least rainfall) are August, September and October (0.59").
Average rainfall days in September
Helmville, MT
- Average rainfall days in September: 6.9 days
The month with the highest number of rainy days is June (13.3 days).
The month with the least rainy days is November (6.5 days).
Average snowfall in September
Helmville, MT
- Average snowfall in September: 0.39"
The month with the highest snowfall is February (9.76").
The months with the least snowfall are July and August (0").
Average snowfall days in September
Helmville, MT
- Average snowfall days in September: 0.5 days
The month with the highest number of snowfall days is February (18.1 days).
The months with the least snowfall days are July and August (0 days).
Average daylight in September /
Average sunshine in September
Helmville, MT
- Average daylight in September: 12h and 30min
The month with the longest days is June (Average daylight: 15h and 48min).
The month with the shortest days is December (Average daylight: 8h and 36min).
- Average sunshine in September: 9h and 48min
The month with the most sunshine is July (Average sunshine: 11h and 54min).
The months with the least sunshine are January and December (Average sunshine: 5h and 36min).
Average sunshine days in September
Helmville, MT
- Average sunshine days in September: 21.9 days
The month with the most sunshine days is September (21.9 days).
The month with the least sunshine days is February (8.5 days).
Average UV index in September
Helmville, MT
- Average UV index in September: 3
The month with the highest UV index is July (UV index 5).
The month with the lowest UV index is January (UV index 1).
Average cloud cover in September
Helmville, MT
- Average cloud cover in September: 20
The month with the most cloud cover is February (Cloud cover 50).
The months with the least cloud cover are July and August (Cloud cover 13).
Average visibility in September
Helmville, MT
- Average visibility in September: 6mi
The months with the highest visibility are May, June, July, August, September and October (6mi).
The months with the lowest visibility are January, February and December (4mi).
