September weather forecastAspen, WY
September
Weather in September
The first month of the autumn, September, is also an agreeable month in Aspen, Wyoming, with an average temperature ranging between max 68.5°F (20.3°C) and min 45°F (7.2°C).Temperature
During the transition into September, Aspen observes a decrease in the average high-temperature, falling from a moderately hot 77.5°F (25.3°C) in August to an agreeable 68.5°F (20.3°C). A pronounced dip becomes evident during the nights in September as Aspen logs a consistent average temperature of 45°F (7.2°C).Humidity
The average relative humidity in September is 44%.Rainfall
In Aspen, during September, the rain falls for 8 days and regularly aggregates up to 0.71" (18mm) of precipitation. Throughout the year, there are 94.2 rainfall days, and 11.5" (292mm) of precipitation is accumulated.Snowfall
January through June, September through December are months with snowfall. September is the first month it typically snows. Throughout September, in the average 1.1 snowfall days, it receives 0.91" (23mm) of snow. In Aspen, during the entire year, snow falls for 99.3 days and aggregates up to 56.22" (1428mm) of snow.Daylight
In September, the average length of the day is 12h and 27min.On the first day of September, sunrise is at 6:50 am and sunset at 7:55 pm. On the last day of the month, sunrise is at 7:19 am and sunset at 7:05 pm MDT.
Sunshine
In September, the average sunshine is 10.3h.UV index
In September, the average daily maximum UV index 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: A daily high UV index of 4 in September leads to these guidelines:
Preventative actions are necessary - Suggestions to safeguard against sun damage are in order. The Sun's most intense and consequently most harmful UV radiation during midday hours should be decreased by minimizing exposure and seeking shade. A hat with a generous brim can prevent nearly 50% of UV rays from reaching your eyes. 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
Average temperature in September
Aspen, WY
- Average high temperature in September: 68.5°F
The warmest month (with the highest average high temperature) is July (79.2°F).
The month with the lowest average high temperature is December (26.4°F).
- Average low temperature in September: 45°F
The month with the highest average low temperature is July (51.6°F).
The coldest month (with the lowest average low temperature) is January (10.8°F).
Average pressure in September
Aspen, WY
- Average pressure in September: 29.96"Hg
The month with the highest atmospheric pressure is January (30.29"Hg).
The month with the lowest atmospheric pressure is June (29.88"Hg).
Average wind speed in September
Aspen, WY
- Average wind speed in September: 7.3mph
The windiest month (with the highest average wind speed) is April (8.2mph).
The calmest month (with the lowest average wind speed) is July (6.7mph).
Average humidity in September
Aspen, WY
- Average humidity in September: 44%
The months with the highest relative humidity are January and February (87%).
The month with the lowest relative humidity is August (39%).
Average rainfall in September
Aspen, WY
- Average rainfall in September: 0.71"
The wettest months (with the highest rainfall) are April and May (1.38").
The driest month (with the least rainfall) is August (0.51").
Average rainfall days in September
Aspen, WY
- Average rainfall days in September: 8 days
The month with the highest number of rainy days is May (11.9 days).
The month with the least rainy days is February (5.5 days).
Average snowfall in September
Aspen, WY
- Average snowfall in September: 0.91"
The month with the highest snowfall is March (10").
The months with the least snowfall are July and August (0").
Average snowfall days in September
Aspen, WY
- Average snowfall days in September: 1.1 days
The month with the highest number of snowfall days is February (16.3 days).
The months with the least snowfall days are July and August (0 days).
Average daylight in September /
Average sunshine in September
Aspen, WY
- Average daylight in September: 12h and 30min
The month with the longest days is June (Average daylight: 15h and 6min).
The month with the shortest days is December (Average daylight: 9h and 18min).
- Average sunshine in September: 10h and 18min
The month with the most sunshine is August (Average sunshine: 12h and 0min).
The month with the least sunshine is January (Average sunshine: 5h and 48min).
Average sunshine days in September
Aspen, WY
- Average sunshine days in September: 17 days
The month with the most sunshine days is June (19.5 days).
The month with the least sunshine days is April (10.8 days).
Average UV index in September
Aspen, WY
- Average UV index in September: 4
The months with the highest UV index are June, July and August (UV index 5).
The months with the lowest UV index are November and December (UV index 1).
Average cloud cover in September
Aspen, WY
- Average cloud cover in September: 13
The month with the most cloud cover is February (Cloud cover 45).
The month with the least cloud cover is August (Cloud cover 10).
Average visibility in September
Aspen, 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).
