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
Start of September brings a shift in the average high-temperature, falling from August's moderately hot 77.5°F (25.3°C) to a comfortable 66.4°F (19.1°C). Chiwaukum, in the heat of September, registers a significant plunge to a mean of 43.2°F (6.2°C) during the nights.Humidity
In Chiwaukum, the average relative humidity in September is 65%.Rainfall
In September, the rain falls for 10.3 days. Throughout September, 1.06" (27mm) of precipitation is accumulated. Throughout the year, there are 159.9 rainfall days, and 25.63" (651mm) of precipitation is accumulated.Snowfall
Months with snowfall are January through May, September through December. September is the first month it typically snows in Chiwaukum. Throughout September, in the average 0.2 snowfall days, it receives 0.39" (10mm) of snow. In Chiwaukum, during the entire year, snow falls for 73.4 days and aggregates up to 57.99" (1473mm) of snow.Daylight
In September, the average length of the day is 12h and 33min.On the first day of September, sunrise is at 6:22 am and sunset at 7:42 pm. On the last day of the month, sunrise is at 7:01 am and sunset at 6:43 pm PDT.
Sunshine
The average sunshine in September is 10.5h.UV index
In Chiwaukum, the average daily maximum UV index in September is 3. A UV Index estimate of 3 to 5 represents a medium health hazard from unprotected exposure to Sun's UV rays for the ordinary person.Note: The maximum UV index of 3 during September translates into these guidelines:
Proceed with care. Light skin individuals may be exposed to burns in fewer than 30 minutes. Direct exposure to the Sun during its peak hours around mid-day should be minimized for safety. Fend off the sun's harsh rays with appropriate clothing, a wide-brim hat, and UV-protective sunglasses. Mind this! Nearly twice the UV radiation from the Sun can be reflected by the 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 many days does it rain in September in Chiwaukum?
When does it start to snow in Chiwaukum?
How many hours of daylight does Chiwaukum have in September?
When is the sunrise / sunset in September?
How long on average sun shines in September?
How high is the UV index in September?
Average temperature in September
Chiwaukum, WA
- Average high temperature in September: 66.4°F
The warmest month (with the highest average high temperature) is August (77.5°F).
The month with the lowest average high temperature is December (30.6°F).
- Average low temperature in September: 43.2°F
The month with the highest average low temperature is August (49.6°F).
The coldest month (with the lowest average low temperature) is December (18.7°F).
Average pressure in September
Chiwaukum, WA
- Average pressure in September: 29.98"Hg
The month with the highest atmospheric pressure is January (30.14"Hg).
The month with the lowest atmospheric pressure is August (29.95"Hg).
Average wind speed in September
Chiwaukum, WA
- Average wind speed in September: 4.7mph
The windiest month (with the highest average wind speed) is June (5.7mph).
The calmest month (with the lowest average wind speed) is December (3.5mph).
Average humidity in September
Chiwaukum, WA
- Average humidity in September: 65%
The month with the highest relative humidity is January (92%).
The months with the lowest relative humidity are July and August (56%).
Average rainfall in September
Chiwaukum, WA
- Average rainfall in September: 1.06"
The wettest month (with the highest rainfall) is January (4.33").
The driest month (with the least rainfall) is July (0.43").
Average rainfall days in September
Chiwaukum, WA
- Average rainfall days in September: 10.3 days
The month with the highest number of rainy days is March (18.2 days).
The month with the least rainy days is August (6.3 days).
Average snowfall in September
Chiwaukum, WA
- Average snowfall in September: 0.39"
The month with the highest snowfall is January (16.73").
The months with the least snowfall are June, July and August (0").
Average snowfall days in September
Chiwaukum, WA
- Average snowfall days in September: 0.2 days
The month with the highest number of snowfall days is December (17 days).
The months with the least snowfall days are June, July and August (0 days).
Average daylight in September /
Average sunshine in September
Chiwaukum, 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 3min
The month with the most sunshine is August (Average sunshine: 11h and 54min).
The month with the least sunshine is January (Average sunshine: 4h and 6min).
Average sunshine days in September
Chiwaukum, WA
- Average sunshine days in September: 16.5 days
The month with the most sunshine days is August (21.9 days).
The month with the least sunshine days is February (6.8 days).
Average UV index in September
Chiwaukum, WA
- Average UV index in September: 3
The month with the highest UV index is July (UV index 6).
The months with the lowest UV index are January and February (UV index 1).
Average cloud cover in September
Chiwaukum, WA
- Average cloud cover in September: 25
The month with the most cloud cover is January (Cloud cover 56).
The month with the least cloud cover is August (Cloud cover 15).
Average visibility in September
Chiwaukum, WA
- Average visibility in September: 6mi
The months with the highest visibility are April, May, June, July, August, September and October (6mi).
The months with the lowest visibility are January, February, March, November and December (4mi).
Chiwaukum, Washington, USA
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