Contents
- Weather in September
- Frequently asked questions
- Average temperature in September
- Average pressure in September
- Average wind speed in September
- Average humidity in September
- Average rainfall in September
- Average rainfall days in September
- Average snowfall in September
- Average snowfall days in September
- Average daylight in September
- Average sunshine in September
- Average sunshine days in September
- Average UV index in September
- Average cloud cover in September
- Average visibility in September
Weather in September
Temperature
The arrival of September indicates a decrease in the average high-temperature, moving from a warm 79.3°F (26.3°C) in August to an agreeable 70.3°F (21.3°C). In Green River, the average temperature during the nights of September drops to a cool 51.3°F (10.7°C).Humidity
In Green River, the average relative humidity in September is 36%.Rainfall
In Green River, during September, the rain falls for 7.2 days and regularly aggregates up to 0.63" (16mm) of precipitation. Throughout the year, there are 93.5 rainfall days, and 10.31" (262mm) of precipitation is accumulated.Snowfall
Months with snowfall in Green River are January through June, September through December. September is the first month it typically snows. Throughout September, in the average 0.2 snowfall days, it receives 0.04" (1mm) of snow. Throughout the year, there are 75.5 snowfall days, and 30.16" (766mm) of snow is accumulated.Daylight
The average length of the day in September is 12h and 28min.On the first day of September in Green River, sunrise is at 6:44 am and sunset at 7:50 pm. On the last day of the month, sunrise is at 7:14 am and sunset at 7:00 pm MDT.
Sunshine
In September, the average sunshine is 10.7h.UV index
In Green River, the average daily maximum UV index in September is 4. A UV Index of 3 to 5 symbolizes a medium health hazard from exposure to the Sun's UV radiation for ordinary individuals.Note: A daily high UV index of 4 in September leads to these guidelines:
Be vigilant - A duty to shield skin and eyes from injury exists. Minimize direct exposure to the Sun during midday when its radiation is at its peak. For minimizing sun-related eye damage, always choose sunglasses with UVA and UVB coverage. Heads up! The UV radiation from the Sun can almost be doubled by snow reflection.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What are September temperatures?
What is the average humidity in September?
How many days does it rain in September?
When does it start to snow?
What is the average length of the day in September?
When are sunrise and sunset in September?
How long on average sun shines in September?
What is the UV index intensity in September?
Average temperature in September
Green River, WY
- Average high temperature in September: 70.3°F
The warmest month (with the highest average high temperature) is July (81.5°F).
The month with the lowest average high temperature is December (25.7°F).
- Average low temperature in September: 51.3°F
The month with the highest average low temperature is July (60.4°F).
The coldest month (with the lowest average low temperature) is January (10.8°F).
Average pressure in September
Green River, WY
- Average pressure in September: 29.98"Hg
The month with the highest atmospheric pressure is January (30.28"Hg).
The month with the lowest atmospheric pressure is June (29.89"Hg).
Average wind speed in September
Green River, WY
- Average wind speed in September: 9.4mph
The windiest month (with the highest average wind speed) is April (12.2mph).
The calmest month (with the lowest average wind speed) is August (8.7mph).
Average humidity in September
Green River, WY
- Average humidity in September: 36%
The month with the highest relative humidity is January (84%).
The months with the lowest relative humidity are July and August (31%).
Average rainfall in September
Green River, WY
- Average rainfall in September: 0.63"
The wettest month (with the highest rainfall) is May (1.5").
The driest month (with the least rainfall) is July (0.47").
Average rainfall days in September
Green River, WY
- Average rainfall days in September: 7.2 days
The month with the highest number of rainy days is May (13.8 days).
The month with the least rainy days is December (4.7 days).
Average snowfall in September
Green River, WY
- Average snowfall in September: 0.04"
The month with the highest snowfall is March (6.14").
The months with the least snowfall are July and August (0").
Average snowfall days in September
Green River, WY
- Average snowfall days in September: 0.2 days
The month with the highest number of snowfall days is December (13.5 days).
The months with the least snowfall days are July and August (0 days).
Average daylight in September /
Average sunshine in September
Green River, WY
- Average daylight in September: 12h and 3min
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 12min).
- Average sunshine in September: 10h and 4min
The months with the most sunshine are July and August (Average sunshine: 11h and 48min).
The months with the least sunshine are January and December (Average sunshine: 5h and 54min).
Average sunshine days in September
Green River, WY
- Average sunshine days in September: 19.8 days
The month with the most sunshine days is September (19.8 days).
The month with the least sunshine days is April (11.5 days).
Average UV index in September
Green River, 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
Green River, WY
- Average cloud cover in September: 14
The month with the most cloud cover is February (Cloud cover 43).
The month with the least cloud cover is August (Cloud cover 13).
Average visibility in September
Green River, 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).
Green River, Wyoming, USA
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