September weather forecastRock River, WY
September
Weather in September
September, the first month of the autumn in Rock River, is also an agreeable month, with an average temperature varying between 46.6°F (8.1°C) and 68.4°F (20.2°C).Temperature
A mild drop in Rock River's average high-temperature is observed in September, transitioning from a warm 75.7°F (24.3°C) in August to a pleasant 68.4°F (20.2°C). Despite high daytime temperatures, the average temperature lowers to a chilly 46.6°F (8.1°C) during September nights.Humidity
The months with the lowest humidity are August and September, with an average relative humidity of 43%.Rainfall
In Rock River, Wyoming, during September, the rain falls for 9.7 days and regularly aggregates up to 1.02" (26mm) of precipitation. In Rock River, Wyoming, during the entire year, the rain falls for 101.4 days and collects up to 14.37" (365mm) of precipitation.Snowfall
January through June, September through December are months with snowfall in Rock River. September is the first month it typically snows in Rock River. Throughout September, in the average 1.1 snowfall days, it receives 0.47" (12mm) of snow. In Rock River, during the entire year, snow falls for 78.1 days and aggregates up to 44.8" (1138mm) of snow.Daylight
In September, the average length of the day in Rock River is 12h and 28min.On the first day of the month, sunrise is at 6:30 am and sunset at 7:36 pm. On the last day of September, in Rock River, Wyoming, sunrise is at 7:00 am and sunset at 6:46 pm MDT.
Sunshine
The average sunshine in September is 10.7h.UV index
In Rock River, Wyoming, the average daily maximum UV index in September is 4. A UV Index estimate of 3 to 5 represents a moderate health risk from exposure to the Sun's UV radiation for ordinary individuals.Note: In September, the average maximum UV index of 4 translates into the following recommendations:
Make use of precautions - Suggestions to resist sunburn are communicated. The solar radiation around mid-day is intense; avoid the Sun and stay safe. Select sunglasses that boast both UVA and UVB protection to limit the adverse effects of the sun on the eyes. Consider carefully! The reflective quality of snow can almost double the intensity of the Sun's UV radiation.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Rock River, WY
- Average high temperature in September: 68.4°F
The warmest month (with the highest average high temperature) is July (76.8°F).
The month with the lowest average high temperature is December (28.2°F).
- Average low temperature in September: 46.6°F
The month with the highest average low temperature is July (54.1°F).
The coldest month (with the lowest average low temperature) is December (14.4°F).
Average pressure in September
Rock River, WY
- Average pressure in September: 29.98"Hg
The month with the highest atmospheric pressure is January (30.17"Hg).
The month with the lowest atmospheric pressure is June (29.88"Hg).
Average wind speed in September
Rock River, WY
- Average wind speed in September: 10.9mph
The windiest month (with the highest average wind speed) is January (14.5mph).
The calmest month (with the lowest average wind speed) is July (9.3mph).
Average humidity in September
Rock River, WY
- Average humidity in September: 43%
The months with the highest relative humidity are January and February (75%).
The months with the lowest relative humidity are August and September (43%).
Average rainfall in September
Rock River, WY
- Average rainfall in September: 1.02"
The wettest month (with the highest rainfall) is May (2.68").
The driest month (with the least rainfall) is January (0.35").
Average rainfall days in September
Rock River, WY
- Average rainfall days in September: 9.7 days
The months with the highest number of rainy days are May and July (15.1 days).
The months with the least rainy days are January, February and November (2.9 days).
Average snowfall in September
Rock River, WY
- Average snowfall in September: 0.47"
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
Rock River, WY
- Average snowfall days in September: 1.1 days
The month with the highest number of snowfall days is April (12.5 days).
The months with the least snowfall days are July and August (0 days).
Average daylight in September /
Average sunshine in September
Rock River, WY
- Average daylight in September: 12h and 30min
The month with the longest days is June (Average daylight: 15h and 12min).
The month with the shortest days is December (Average daylight: 9h and 12min).
- Average sunshine in September: 10h and 42min
The month with the most sunshine is July (Average sunshine: 11h and 36min).
The month with the least sunshine is December (Average sunshine: 6h and 24min).
Average sunshine days in September
Rock River, WY
- Average sunshine days in September: 16.7 days
The month with the most sunshine days is January (21.4 days).
The month with the least sunshine days is May (8.9 days).
Average UV index in September
Rock River, 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 January, February, March, April, October, November and December (UV index 2).
Average cloud cover in September
Rock River, WY
- Average cloud cover in September: 17
The month with the most cloud cover is February (Cloud cover 34).
The month with the least cloud cover is September (Cloud cover 17).
Average visibility in September
Rock River, 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).
