September weather forecastRiverside, WY
September
Weather in September
September, the first month of the autumn in Riverside, is also an agreeable month, with temperature in the range of an average high of 68.5°F (20.3°C) and an average low of 45°F (7.2°C).Temperature
The onset of September entails a subtle temperature shift, as the average high-temperature eases from a moderately hot 76.3°F (24.6°C) in August to a pleasant 68.5°F (20.3°C). From the height of daytime heat, the temperature recedes to an average of 45°F (7.2°C) at night during September.Humidity
In September, the average relative humidity in Riverside, Wyoming, is 43%.Rainfall
The months with the least rainfall in Riverside are August and September Rain falls for 9 days and accumulates 0.75" (19mm) of rain.Snowfall
Months with snowfall are January through June, September through December. September is the first month it typically snows. Throughout September, in the average 0.8 snowfall days, it receives 0.28" (7mm) of snow. In Riverside, during the entire year, snow falls for 101 days and aggregates up to 54.49" (1384mm) of snow.Daylight
In Riverside, the average length of the day in September is 12h and 27min.On the first day of September, sunrise is at 6:34 am and sunset at 7:39 pm. On the last day of the month, sunrise is at 7:03 am and sunset at 6:50 pm MDT.
Sunshine
In Riverside, Wyoming, the average sunshine in September is 10.9h.UV index
The average daily maximum UV index in September in Riverside is 4. A UV Index reading of 3 to 5 represents a medium health hazard from unsafe exposure to UV radiation for the average person.Note: The maximum UV index of 4 during September leads to these instructions:
Make use of precautions - Shielding skin and eyes from injury is a requirement. Avoiding the Sun during its peak radiation time around midday is a healthy practice. Sun-related eye harm can be minimized with proper sunglasses offering UVA and UVB coverage. Be prepared! The intensity of the Sun's UV radiation can be amplified nearly double due to snow reflection.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Riverside, WY
- Average high temperature in September: 68.5°F
The warmest month (with the highest average high temperature) is July (77.9°F).
The month with the lowest average high temperature is December (25.7°F).
- Average low temperature in September: 45°F
The month with the highest average low temperature is July (52.3°F).
The coldest months (with the lowest average low temperature) are January and December (12.9°F).
Average pressure in September
Riverside, WY
- Average pressure in September: 29.99"Hg
The month with the highest atmospheric pressure is January (30.23"Hg).
The month with the lowest atmospheric pressure is June (29.89"Hg).
Average wind speed in September
Riverside, WY
- Average wind speed in September: 10.1mph
The windiest month (with the highest average wind speed) is November (11.8mph).
The calmest month (with the lowest average wind speed) is July (9.1mph).
Average humidity in September
Riverside, WY
- Average humidity in September: 43%
The month with the highest relative humidity is February (84%).
The month with the lowest relative humidity is August (41%).
Average rainfall in September
Riverside, WY
- Average rainfall in September: 0.75"
The wettest month (with the highest rainfall) is April (1.97").
The driest months (with the least rainfall) are August and September (0.75").
Average rainfall days in September
Riverside, WY
- Average rainfall days in September: 9 days
The month with the highest number of rainy days is May (14.7 days).
The month with the least rainy days is November (4.9 days).
Average snowfall in September
Riverside, WY
- Average snowfall in September: 0.28"
The month with the highest snowfall is April (9.76").
The months with the least snowfall are July and August (0").
Average snowfall days in September
Riverside, WY
- Average snowfall days in September: 0.8 days
The month with the highest number of snowfall days is February (17.1 days).
The months with the least snowfall days are July and August (0 days).
Average daylight in September /
Average sunshine in September
Riverside, 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 54min
The months with the most sunshine are July and August (Average sunshine: 11h and 48min).
The month with the least sunshine is February (Average sunshine: 5h and 30min).
Average sunshine days in September
Riverside, WY
- Average sunshine days in September: 16.8 days
The month with the most sunshine days is September (16.8 days).
The month with the least sunshine days is February (9.4 days).
Average UV index in September
Riverside, WY
- Average UV index in September: 4
The months with the highest UV index are June, July and August (UV index 5).
The month with the lowest UV index is December (UV index 1).
Average cloud cover in September
Riverside, WY
- Average cloud cover in September: 14
The month with the most cloud cover is February (Cloud cover 47).
The months with the least cloud cover are August and September (Cloud cover 14).
Average visibility in September
Riverside, WY
- Average visibility in September: 6mi
The months with the highest visibility are March, April, May, June, July, August, September, October and November (6mi).
The months with the lowest visibility are January, February and December (5mi).
