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
With the advent of September, Chinook experiences an average high-temperature of a still enjoyable 62.6°F (17°C), mirroring a close resemblance to the previous month. A modest decline from daytime high temperatures is noticed in September, marking the average low at a fresh 55°F (12.8°C).Humidity
In Chinook, the average relative humidity in September is 83%.Rainfall
In Chinook, in September, it is raining for 9.9 days, with typically 0.94" (24mm) of accumulated precipitation. Throughout the year, there are 165.1 rainfall days, and 19.92" (506mm) of precipitation is accumulated.Snowfall
January, February and September are months with snowfall in Chinook. September is the first month it typically snows. Throughout September, in the average 0.1 snowfall days, it receives 0.04" (1mm) of snow. Throughout the year, there are 1.8 snowfall days, and 0.47" (12mm) of snow is accumulated.Daylight
In September, the average length of the day is 12h and 31min.On the first day of the month, sunrise is at 6:37 am and sunset at 7:53 pm. On the last day of September, sunrise is at 7:14 am and sunset at 6:56 pm PDT.
Sunshine
The average sunshine in September is 8.7h.UV index
May through September, with an average maximum UV index of 4, are months with the highest UV index. A UV Index estimate of 3 to 5 represents a moderate threat to health from exposure to the Sun's UV radiation for the ordinary person.Note: A maximum daily UV index of 4 during September morphs into the following directions:
Preventative actions are necessary - Recommendations to ward off sunburn are given. The Sun's most harmful UV rays are emitted around midday; avoid staying outdoors for long during this time. Counter UV radiation's ill effects with clothing designed for sun safety and UV-resistant eyewear. Mind you! Snow reflection can increase the intensity of the Sun's UV radiation nearly twofold.
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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 in Chinook?
When does it start to snow?
What is the average length of the day in September?
When are sunrise and sunset in September?
How long on average sun shines in September?
What are the months with the highest UV index?
How high is the UV index in September?
Average temperature in September
Chinook, WA
- Average high temperature in September: 62.6°F
The warmest month (with the highest average high temperature) is August (63.9°F).
The month with the lowest average high temperature is December (46.8°F).
- Average low temperature in September: 55°F
The month with the highest average low temperature is August (55.9°F).
The coldest month (with the lowest average low temperature) is December (41.5°F).
Average pressure in September
Chinook, WA
- Average pressure in September: 30.02"Hg
The month with the highest atmospheric pressure is July (30.08"Hg).
The month with the lowest atmospheric pressure is March (30.01"Hg).
Average wind speed in September
Chinook, WA
- Average wind speed in September: 7.8mph
The windiest month (with the highest average wind speed) is January (11.9mph).
The calmest month (with the lowest average wind speed) is August (7.1mph).
Average humidity in September
Chinook, WA
- Average humidity in September: 83%
The month with the highest relative humidity is August (86%).
The month with the lowest relative humidity is April (80%).
Average rainfall in September
Chinook, WA
- Average rainfall in September: 0.94"
The wettest month (with the highest rainfall) is December (3.31").
The driest month (with the least rainfall) is July (0.35").
Average rainfall days in September
Chinook, WA
- Average rainfall days in September: 9.9 days
The month with the highest number of rainy days is November (18.5 days).
The month with the least rainy days is August (6.7 days).
Average snowfall in September
Chinook, WA
- Average snowfall in September: 0.04"
The month with the highest snowfall is February (0.31").
The months with the least snowfall are March, April, May, June, July, August, October, November and December (0").
Average snowfall days in September
Chinook, WA
- Average snowfall days in September: 0.1 days
The month with the highest number of snowfall days is February (0.8 days).
The months with the least snowfall days are April, May, June, July, August and October (0 days).
Average daylight in September /
Average sunshine in September
Chinook, WA
- Average daylight in September: 12h and 3min
The month with the longest days is June (Average daylight: 15h and 42min).
The month with the shortest days is December (Average daylight: 8h and 42min).
- Average sunshine in September: 8h and 4min
The month with the most sunshine is July (Average sunshine: 9h and 42min).
The month with the least sunshine is January (Average sunshine: 3h and 48min).
Average sunshine days in September
Chinook, WA
- Average sunshine days in September: 17.1 days
The month with the most sunshine days is August (20.3 days).
The month with the least sunshine days is November (8.9 days).
Average UV index in September
Chinook, WA
- Average UV index in September: 4
The months with the highest UV index are May, June, July, August and September (UV index 4).
The months with the lowest UV index are February, November and December (UV index 2).
Average cloud cover in September
Chinook, WA
- Average cloud cover in September: 37
The month with the most cloud cover is January (Cloud cover 60).
The months with the least cloud cover are August and September (Cloud cover 37).
Average visibility in September
Chinook, WA
- 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).
Chinook, Washington, USA
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