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 transition into September indicates a reduction in the average high-temperature, down to a pleasant 72.7°F (22.6°C) from August's moderately hot 84.2°F (29°C). In Coulee City, the average nighttime temperature during September is a cool 53.2°F (11.8°C).Humidity
In Coulee City, the average relative humidity in September is 45%.Rainfall
In Coulee City, in September, during 5.5 rainfall days, 0.43" (11mm) of precipitation is typically accumulated. In Coulee City, during the entire year, the rain falls for 102.1 days and collects up to 9.65" (245mm) of precipitation.Snowfall
January through April, September through December are months with snowfall. September is the first month it typically snows in Coulee City. Throughout September, in the average 0.1 snowfall days, it receives 0.08" (2mm) of snow. Throughout the year, there are 33.4 snowfall days, and 14.65" (372mm) of snow is accumulated.Daylight
In September, the average length of the day is 12h and 33min.On the first day of September in Coulee City, sunrise is at 6:16 am and sunset at 7:36 pm. On the last day of the month, sunrise is at 6:56 am and sunset at 6:37 pm PDT.
Sunshine
The average sunshine in September is 10.7h.UV index
The average daily maximum UV index in September is 4. A UV Index of 3 to 5 symbolizes a moderate health risk from exposure to the Sun's UV radiation for ordinary individuals.Note: The UV index of 4 during September leads to these advisories:
Take precautions - Protection against skin and eye damage is obliged. Solar radiation is at its peak intensity during midday, so it's advisable to stay indoors or in the shade. Sunglasses providing both UVA and UVB protection are non-negotiable on sunlit days. Be careful! The Sun's UV radiation can nearly be doubled by the reflective quality of snow.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What is the temperature in September?
What is the average humidity in September?
How much does it rain in Coulee City in September?
When does it start snowing?
What is the average length of the day in September?
When are sunrise and sunset in September?
How many hours of sunshine does Coulee City have in September?
How high is the UV index in September?
Average temperature in September
Coulee City, WA
- Average high temperature in September: 72.7°F
The warmest month (with the highest average high temperature) is July (84.9°F).
The month with the lowest average high temperature is December (31.6°F).
- Average low temperature in September: 53.2°F
The month with the highest average low temperature is August (61.3°F).
The coldest month (with the lowest average low temperature) is December (21.4°F).
Average pressure in September
Coulee City, WA
- Average pressure in September: 29.96"Hg
The month with the highest atmospheric pressure is January (30.18"Hg).
The month with the lowest atmospheric pressure is August (29.91"Hg).
Average wind speed in September
Coulee City, WA
- Average wind speed in September: 5.8mph
The windiest month (with the highest average wind speed) is April (7mph).
The calmest month (with the lowest average wind speed) is January (4.9mph).
Average humidity in September
Coulee City, WA
- Average humidity in September: 45%
The month with the highest relative humidity is January (89%).
The month with the lowest relative humidity is August (36%).
Average rainfall in September
Coulee City, WA
- Average rainfall in September: 0.43"
The wettest months (with the highest rainfall) are May and December (1.18").
The driest months (with the least rainfall) are July and August (0.2").
Average rainfall days in September
Coulee City, WA
- Average rainfall days in September: 5.5 days
The month with the highest number of rainy days is March (12.1 days).
The month with the least rainy days is August (3.2 days).
Average snowfall in September
Coulee City, WA
- Average snowfall in September: 0.08"
The month with the highest snowfall is January (4.41").
The months with the least snowfall are May, June, July and August (0").
Average snowfall days in September
Coulee City, WA
- Average snowfall days in September: 0.1 days
The month with the highest number of snowfall days is December (10.5 days).
The months with the least snowfall days are May, June, July and August (0 days).
Average daylight in September /
Average sunshine in September
Coulee City, WA
- Average daylight in September: 12h and 3min
The month with the longest days is June (Average daylight: 15h and 54min).
The month with the shortest days is December (Average daylight: 8h and 30min).
- Average sunshine in September: 10h and 4min
The month with the most sunshine is August (Average sunshine: 12h and 6min).
The month with the least sunshine is January (Average sunshine: 4h and 6min).
Average sunshine days in September
Coulee City, WA
- Average sunshine days in September: 23.3 days
The month with the most sunshine days is August (25.8 days).
The month with the least sunshine days is March (14.7 days).
Average UV index in September
Coulee City, WA
- Average UV index in September: 4
The month with the highest UV index is July (UV index 7).
The month with the lowest UV index is November (UV index 1).
Average cloud cover in September
Coulee City, WA
- Average cloud cover in September: 18
The month with the most cloud cover is January (Cloud cover 55).
The months with the least cloud cover are July and August (Cloud cover 12).
Average visibility in September
Coulee City, WA
- 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 and December (4mi).
Coulee City, Washington, USA
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