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
September heralds a minor drop in average high-temperature, sliding from August's moderately hot 77.4°F (25.2°C) to an agreeable 68.7°F (20.4°C). An average nighttime temperature of 48.7°F (9.3°C) is observed during September.Humidity
In September, the average relative humidity is 48%.Rainfall
In Story, in September, during 12.5 rainfall days, 1.42" (36mm) of precipitation is typically accumulated. Throughout the year, there are 165.2 rainfall days, and 21.22" (539mm) of precipitation is accumulated.Snowfall
January through May, September through December are months with snowfall. September is the first month it typically snows. Throughout September, in the average 0.3 snowfall days, it receives 0.35" (9mm) of snow. In Story, during the entire year, snow falls for 78.9 days and aggregates up to 46.3" (1176mm) of snow.Daylight
The average length of the day in September is 12h and 30min.On the first day of September, sunrise is at 6:31 am and sunset at 7:43 pm. On the last day of the month, sunrise is at 7:05 am and sunset at 6:49 pm MDT.
Sunshine
In September, the average sunshine is 10.8h.UV index
In Story, the average daily maximum UV index in September is 4. A UV Index value of 3 to 5 symbolizes a medium health hazard from unprotected exposure to Sun's UV rays for average individuals.Note: An average maximum UV index of 4 in September leads to these recommendations:
Be cautious. Those with fair skin can be subjected to burns in fewer than 30 minutes. The solar radiation is most powerful near the mid-day, so the exposure to the direct Sun should be reduced accordingly. On bright days sunglasses that block both UVA and UVB rays should be worn. A hat with a wide brim is extremely helpful, as it can prevent roughly 50% of UV radiation from reaching the eyes. Notice this! Nearly double the intensity of the Sun's UV radiation can be caused by snow reflection.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What is the average September temperature?
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?
What time are sunrise and sunset in September?
How many hours of sunshine does Story have in September?
What is the UV index reading in September?
Average temperature in September
Story, WY
- Average high temperature in September: 68.7°F
The warmest month (with the highest average high temperature) is July (78.8°F).
The month with the lowest average high temperature is February (29.1°F).
- Average low temperature in September: 48.7°F
The month with the highest average low temperature is July (57°F).
The coldest month (with the lowest average low temperature) is February (14.4°F).
Average pressure in September
Story, WY
- Average pressure in September: 29.93"Hg
The month with the highest atmospheric pressure is January (30.13"Hg).
The month with the lowest atmospheric pressure is June (29.85"Hg).
Average wind speed in September
Story, WY
- Average wind speed in September: 6.3mph
The windiest month (with the highest average wind speed) is April (7.6mph).
The calmest months (with the lowest average wind speed) are July and August (5.8mph).
Average humidity in September
Story, WY
- Average humidity in September: 48%
The month with the highest relative humidity is February (79%).
The month with the lowest relative humidity is August (46%).
Average rainfall in September
Story, WY
- Average rainfall in September: 1.42"
The wettest month (with the highest rainfall) is May (3.43").
The driest month (with the least rainfall) is December (0.75").
Average rainfall days in September
Story, WY
- Average rainfall days in September: 12.5 days
The month with the highest number of rainy days is May (22.3 days).
The month with the least rainy days is November (7.5 days).
Average snowfall in September
Story, WY
- Average snowfall in September: 0.35"
The month with the highest snowfall is April (8.7").
The months with the least snowfall are June, July and August (0").
Average snowfall days in September
Story, WY
- Average snowfall days in September: 0.3 days
The month with the highest number of snowfall days is February (15.8 days).
The months with the least snowfall days are June, July and August (0 days).
Average daylight in September /
Average sunshine in September
Story, WY
- Average daylight in September: 12h and 3min
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 5min
The month with the most sunshine is July (Average sunshine: 11h and 54min).
The month with the least sunshine is February (Average sunshine: 6h and 6min).
Average sunshine days in September
Story, WY
- Average sunshine days in September: 13.6 days
The month with the most sunshine days is November (15.2 days).
The month with the least sunshine days is May (5.8 days).
Average UV index in September
Story, 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
Story, WY
- Average cloud cover in September: 18
The months with the most cloud cover are February and April (Cloud cover 37).
The month with the least cloud cover is July (Cloud cover 15).
Average visibility in September
Story, 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).
Story, Wyoming, USA
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