September weather forecastHeart Butte, MT
September
Weather in September
The first month of the autumn, September, is also an enjoyable month in Heart Butte, Montana, with an average temperature varying between 67.6°F (19.8°C) and 48.4°F (9.1°C).Temperature
Start of September brings a shift in the average high-temperature, falling from August's moderately hot 78.1°F (25.6°C) to a comfortable 67.6°F (19.8°C). In Heart Butte, the average temperature during the nights of September drops to a frosty 48.4°F (9.1°C).Humidity
In Heart Butte, the average relative humidity in September is 49%.Rainfall
In Heart Butte, in September, it is raining for 6.2 days, with typically 0.71" (18mm) of accumulated precipitation. Throughout the year, there are 70.4 rainfall days, and 8.46" (215mm) of precipitation is accumulated.Snowfall
January through May, September through December are months with snowfall. September is the first month it typically snows. Throughout September, in the average 0.8 snowfall days, it receives 0.51" (13mm) of snow. Throughout the year, in Heart Butte, there are 54.3 snowfall days, and 19.49" (495mm) of snow is accumulated.Daylight
In September, the average length of the day is 12h and 34min.On the first day of September, sunrise is at 6:50 am and sunset at 8:12 pm. On the last day of the month, sunrise is at 7:30 am and sunset at 7:11 pm MDT.
Sunshine
In Heart Butte, the average sunshine in September is 9.6h.UV index
The average daily maximum UV index in September is 4. A UV Index reading of 3 to 5 represents a moderate health risk from exposure to the Sun's UV rays for average individuals.Note: The maximum UV index of 4 during September translates into these guidelines:
Preventative actions are necessary - The mandate to avoid skin and eye damage is in place. UV radiation is strongest from the Sun during midday; protect yourself by staying in shaded areas. A wide-brimmed hat provides unparalleled sun protection for sensitive areas like the eyes, ears, and neck. 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
Average temperature in September
Heart Butte, 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
Heart Butte, 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
Heart Butte, 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
Heart Butte, 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
Heart Butte, 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
Heart Butte, 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
Heart Butte, 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
Heart Butte, 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
Heart Butte, MT
- Average daylight in September: 12h and 36min
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 24min).
- Average sunshine in September: 9h and 36min
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
Heart Butte, 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
Heart Butte, 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
Heart Butte, 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
Heart Butte, 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).
