September weather forecastGreybull, WY
September
Weather in September
September signifies the arrival of Autumn in Greybull, Wyoming. The high temperature recedes to a more moderate 73.2°F (22.9°C). A perceptible dip in the amount of daylight gradually ushers in shorter days and longer nights. The lush greenery starts turning into a vibrant mix of orange, yellow, and brown hues. Although the city receives less sunshine, quality weather with low winds and fair conditions remains prevalent.Temperature
In the transition to September, Greybull observes a drop in the average high-temperature, moving from a moderately hot 82.6°F (28.1°C) in August to an agreeable 73.2°F (22.9°C). An average minimum temperature of 53.8°F (12.1°C) is recorded in Greybull during the month of September.Humidity
In September, the average relative humidity is 36%.Rainfall
In September, in Greybull, the rain falls for 6.6 days. Throughout September, 0.71" (18mm) of precipitation is accumulated. In Greybull, during the entire year, the rain falls for 103.2 days and collects up to 5.71" (145mm) of precipitation.Snowfall
June through September are months without snowfall in Greybull.Daylight
The average length of the day in September in Greybull is 12h and 30min.On the first day of September in Greybull, sunrise is at 6:35 am and sunset at 7:48 pm. On the last day of the month, sunrise is at 7:09 am and sunset at 6:54 pm MDT.
Sunshine
The average sunshine in September is 10.9h.UV index
The average daily maximum UV index in September in Greybull is 4. A UV Index of 3 to 5 symbolizes a medium health hazard from unprotected exposure to Sun's UV rays for the average person.Note: In September, a regular UV index of 4 translates into these guidelines:
Undertake precautions - It is suggested to shield oneself from sunburn. The Sun's most intense and consequently most harmful UV radiation during midday hours should be decreased by minimizing exposure and seeking shade. By wearing a generously brimmed hat, you can cut UV radiation exposure significantly. Stay alert! Snow's reflective properties can almost double the UV radiation from the Sun.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Greybull, WY
- Average high temperature in September: 73.2°F
The warmest month (with the highest average high temperature) is July (85.1°F).
The month with the lowest average high temperature is December (28.8°F).
- Average low temperature in September: 53.8°F
The month with the highest average low temperature is July (63.3°F).
The coldest month (with the lowest average low temperature) is January (13.8°F).
Average pressure in September
Greybull, WY
- Average pressure in September: 29.96"Hg
The month with the highest atmospheric pressure is January (30.16"Hg).
The month with the lowest atmospheric pressure is June (29.87"Hg).
Average wind speed in September
Greybull, WY
- Average wind speed in September: 6.6mph
The windiest month (with the highest average wind speed) is April (8.3mph).
The calmest months (with the lowest average wind speed) are January and August (6mph).
Average humidity in September
Greybull, WY
- Average humidity in September: 36%
The month with the highest relative humidity is January (78%).
The months with the lowest relative humidity are July and August (33%).
Average rainfall in September
Greybull, WY
- Average rainfall in September: 0.71"
The wettest month (with the highest rainfall) is May (0.87").
The driest month (with the least rainfall) is December (0.2").
Average rainfall days in September
Greybull, WY
- Average rainfall days in September: 6.6 days
The month with the highest number of rainy days is May (12.6 days).
The month with the least rainy days is December (6.5 days).
Average snowfall in September
Greybull, WY
- Average snowfall in September: 0"
The month with the highest snowfall is February (2.52").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in September
Greybull, WY
- Average snowfall days in September: 0.1 days
The month with the highest number of snowfall days is February (9.8 days).
The months with the least snowfall days are June, July and August (0 days).
Average daylight in September /
Average sunshine in September
Greybull, WY
- Average daylight in September: 12h and 30min
The month with the longest days is June (Average daylight: 15h and 30min).
The month with the shortest days is December (Average daylight: 8h and 54min).
- Average sunshine in September: 10h and 54min
The months with the most sunshine are June, July and August (Average sunshine: 11h and 54min).
The month with the least sunshine is January (Average sunshine: 6h and 42min).
Average sunshine days in September
Greybull, WY
- Average sunshine days in September: 18.5 days
The month with the most sunshine days is December (20.9 days).
The months with the least sunshine days are April and June (12.5 days).
Average UV index in September
Greybull, WY
- Average UV index in September: 4
The months with the highest UV index are June, July and August (UV index 6).
The months with the lowest UV index are January, February, March, November and December (UV index 2).
Average cloud cover in September
Greybull, WY
- Average cloud cover in September: 13
The month with the most cloud cover is February (Cloud cover 28).
The months with the least cloud cover are July and August (Cloud cover 12).
Average visibility in September
Greybull, WY
- 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).
