September weather forecastFrontier, WY
September
Weather in September
The first month of the autumn, September, is also an agreeable month in Frontier, Wyoming, with an average temperature ranging between min 47.7°F (8.7°C) and max 68.9°F (20.5°C).Temperature
September's arrival comes with a decrease in the average high-temperature, moving from a moderately hot 77.9°F (25.5°C) in August to a pleasant 68.9°F (20.5°C). In September, Frontier experiences an average nighttime temperature of 47.7°F (8.7°C).Humidity
The average relative humidity in September is 40%.Rainfall
In Frontier, during September, the rain falls for 8.6 days and regularly aggregates up to 0.83" (21mm) of precipitation. Throughout the year, there are 96.8 rainfall days, and 11.46" (291mm) of precipitation is accumulated.Snowfall
Months with snowfall are January through June, September through December. September is the first month it typically snows. Throughout September, in the average 0.7 snowfall days, it receives 0.35" (9mm) of snow. In Frontier, during the entire year, snow falls for 88.9 days and aggregates up to 38.86" (987mm) of snow.Daylight
The average length of the day in September is 12h and 28min.On the first day of September, sunrise is at 6:48 am and sunset at 7:54 pm. On the last day of the month, sunrise is at 7:18 am and sunset at 7:04 pm MDT.
Sunshine
In September, the average sunshine is 10.5h.UV index
In Frontier, the average daily maximum UV index in September is 4. A UV Index estimate of 3 to 5 represents a medium health hazard from exposure to the Sun's UV radiation for ordinary individuals.Note: A daily maximum UV index of 4 in September translates into the following instructions:
Be vigilant - A duty to shield skin and eyes from injury exists. To avoid the Sun's strongest rays, limit exposure around the mid-day period. Consider a wide-brim hat essential for effective sun defense covering your face, neck, and eyes. Take heed! Reflection from the snow can almost amplify the Sun's UV radiation by double.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Frontier, WY
- Average high temperature in September: 68.9°F
The warmest month (with the highest average high temperature) is July (79.3°F).
The month with the lowest average high temperature is December (25.7°F).
- Average low temperature in September: 47.7°F
The month with the highest average low temperature is July (55°F).
The coldest month (with the lowest average low temperature) is January (9.9°F).
Average pressure in September
Frontier, WY
- Average pressure in September: 29.97"Hg
The month with the highest atmospheric pressure is January (30.29"Hg).
The month with the lowest atmospheric pressure is June (29.89"Hg).
Average wind speed in September
Frontier, WY
- Average wind speed in September: 8.3mph
The windiest month (with the highest average wind speed) is April (9.8mph).
The calmest month (with the lowest average wind speed) is July (7.5mph).
Average humidity in September
Frontier, WY
- Average humidity in September: 40%
The months with the highest relative humidity are January and February (87%).
The month with the lowest relative humidity is August (35%).
Average rainfall in September
Frontier, WY
- Average rainfall in September: 0.83"
The wettest month (with the highest rainfall) is May (2.01").
The driest month (with the least rainfall) is August (0.59").
Average rainfall days in September
Frontier, WY
- Average rainfall days in September: 8.6 days
The month with the highest number of rainy days is May (13.3 days).
The month with the least rainy days is February (5 days).
Average snowfall in September
Frontier, WY
- Average snowfall in September: 0.35"
The month with the highest snowfall is March (6.81").
The months with the least snowfall are July and August (0").
Average snowfall days in September
Frontier, WY
- Average snowfall days in September: 0.7 days
The month with the highest number of snowfall days is February (15.3 days).
The months with the least snowfall days are July and August (0 days).
Average daylight in September /
Average sunshine in September
Frontier, WY
- Average daylight in September: 12h and 30min
The month with the longest days is June (Average daylight: 15h and 12min).
The month with the shortest days is December (Average daylight: 9h and 12min).
- Average sunshine in September: 10h and 30min
The months with the most sunshine are July and August (Average sunshine: 11h and 48min).
The month with the least sunshine is January (Average sunshine: 5h and 42min).
Average sunshine days in September
Frontier, WY
- Average sunshine days in September: 19.3 days
The month with the most sunshine days is October (19.4 days).
The month with the least sunshine days is April (9.7 days).
Average UV index in September
Frontier, WY
- 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, April, October, November and December (UV index 2).
Average cloud cover in September
Frontier, WY
- Average cloud cover in September: 14
The month with the most cloud cover is February (Cloud cover 47).
The month with the least cloud cover is August (Cloud cover 12).
Average visibility in September
Frontier, WY
- Average visibility in September: 6mi
The months with the highest visibility are April, May, June, July, August, September, October and November (6mi).
The months with the lowest visibility are January and February (4mi).





