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 onset of September, Chehalis's average high-temperature slightly adjusts, moderately receding from August's warm 77.5°F (25.3°C) to a pleasant 70.3°F (21.3°C). The average low-temperature of 46.9°F (8.3°C) in September represents a significant drop from the daily high.Humidity
The average relative humidity in September is 79%.Rainfall
In Chehalis, during September, the rain falls for 11.3 days and regularly aggregates up to 1.65" (42mm) of precipitation. In Chehalis, during the entire year, the rain falls for 185.5 days and collects up to 36.1" (917mm) of precipitation.Snowfall
In Chehalis, snow does not fall in April through October.Daylight
In Chehalis, Washington, the average length of the day in September is 12h and 32min.On the first day of September, sunrise is at 6:32 am and sunset at 7:50 pm. On the last day of the month, sunrise is at 7:10 am and sunset at 6:52 pm PDT.
Sunshine
In Chehalis, the average sunshine in September is 8.3h.UV index
The average daily maximum UV index in September is 3. A UV Index reading of 3 to 5 represents a moderate threat to health from unprotected exposure to Sun's UV rays for the ordinary person.Note: A maximum high daily UV index of 3 during September translates into the following directions:
Be vigilant - Preventing sunburn is recommended. Avoiding direct sunlight during midday hours helps reduce the risk from intense UV radiation. Experience reduced UV exposure by about half when donning a wide-brim hat.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What is the usual temperature for Chehalis in September?
What is the average humidity in September?
How much does it rain in Chehalis in September?
When it does not snow?
How many hours of daylight does Chehalis have in September?
What time are sunrise and sunset in September?
How long on average sun shines in September?
What is the UV index intensity in September?
Average temperature in September
Chehalis, WA
- Average high temperature in September: 70.3°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 (42.6°F).
- Average low temperature in September: 46.9°F
The month with the highest average low temperature is August (50°F).
The coldest month (with the lowest average low temperature) is December (33.1°F).
Average pressure in September
Chehalis, WA
- Average pressure in September: 30.02"Hg
The month with the highest atmospheric pressure is January (30.09"Hg).
The months with the lowest atmospheric pressure are March, August and September (30.02"Hg).
Average wind speed in September
Chehalis, WA
- Average wind speed in September: 3.6mph
The windiest months (with the highest average wind speed) are January, March and November (4.5mph).
The calmest month (with the lowest average wind speed) is September (3.6mph).
Average humidity in September
Chehalis, WA
- Average humidity in September: 79%
The months with the highest relative humidity are January, February, November and December (89%).
The month with the lowest relative humidity is July (73%).
Average rainfall in September
Chehalis, WA
- Average rainfall in September: 1.65"
The wettest month (with the highest rainfall) is January (5.51").
The driest month (with the least rainfall) is July (0.47").
Average rainfall days in September
Chehalis, WA
- Average rainfall days in September: 11.3 days
The month with the highest number of rainy days is March (21.5 days).
The month with the least rainy days is August (6.4 days).
Average snowfall in September
Chehalis, WA
- Average snowfall in September: 0"
The month with the highest snowfall is February (1.93").
The months with the least snowfall are April, May, June, July, August, September and October (0").
Average snowfall days in September
Chehalis, WA
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is February (3.5 days).
The months with the least snowfall days are May, June, July, August, September and October (0 days).
Average daylight in September /
Average sunshine in September
Chehalis, WA
- Average daylight in September: 12h and 3min
The month with the longest days is June (Average daylight: 15h and 48min).
The month with the shortest days is December (Average daylight: 8h and 36min).
- Average sunshine in September: 8h and 2min
The month with the most sunshine is August (Average sunshine: 10h and 12min).
The month with the least sunshine is December (Average sunshine: 3h and 30min).
Average sunshine days in September
Chehalis, WA
- Average sunshine days in September: 16.9 days
The months with the most sunshine days are July and August (20.8 days).
The month with the least sunshine days is February (7.6 days).
Average UV index in September
Chehalis, WA
- Average UV index in September: 3
The month with the highest UV index is July (UV index 5).
The months with the lowest UV index are January, February, November and December (UV index 2).
Average cloud cover in September
Chehalis, WA
- Average cloud cover in September: 47
The months with the most cloud cover are January, February and December (Cloud cover 65).
The month with the least cloud cover is August (Cloud cover 38).
Average visibility in September
Chehalis, WA
- Average visibility in September: 4mi
The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (4mi).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (4mi).
Chehalis, Washington, USA
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