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 start of September involves a subtle temperature drop, shifting from a warm 79.3°F (26.3°C) in August to a pleasant 71.6°F (22°C). Compared to daytime temperatures, Forest Grove's temperature drops significantly, averaging a frosty 49.8°F (9.9°C) during the nights of September.Humidity
In September, the average relative humidity is 74%.Rainfall
In Forest Grove, during September, the rain falls for 11.4 days and regularly aggregates up to 1.57" (40mm) of precipitation. In Forest Grove, during the entire year, the rain falls for 183.5 days and collects up to 34.45" (875mm) of precipitation.Snowfall
In Forest Grove, snow does not fall in April through October.Daylight
In Forest Grove, the average length of the day in September is 12h and 31min.On the first day of the month, sunrise is at 6:34 am and sunset at 7:49 pm. On the last day of September, sunrise is at 7:10 am and sunset at 6:53 pm PDT.
Sunshine
In Forest Grove, the average sunshine in September is 8.7h.UV index
The average daily maximum UV index in September in Forest Grove is 4. A UV Index estimate of 3 to 5 represents a medium health hazard from unsafe exposure to UV radiation for the ordinary person.Note: In September, the average maximum UV index of 4 translates into the following recommendations:
Be careful. Light complexion individuals might get burns in fewer than 30 minutes. Solar radiation is at its peak intensity during midday, so it's advisable to stay indoors or in the shade. To mitigate harm from sun exposure, pick sunglasses offering UVA and UVB defense.
Frequently asked questions
What is the average September temperature in Forest Grove?
What is the average humidity in September in Forest Grove?
How many days does it rain in September in Forest Grove?
When it does not snow in Forest Grove?
How many hours of daylight does Forest Grove have in September?
What time are sunrise and sunset in September in Forest Grove?
How many hours of sunshine does Forest Grove have in September?
What is the UV index intensity in September in Forest Grove?
Average temperature in September
Forest Grove, OR
- Average high temperature in September: 71.6°F
The warmest month (with the highest average high temperature) is August (79.3°F).
The month with the lowest average high temperature is December (43°F).
- Average low temperature in September: 49.8°F
The month with the highest average low temperature is August (53.2°F).
The coldest month (with the lowest average low temperature) is December (33.1°F).
Average pressure in September
Forest Grove, OR
- Average pressure in September: 30.01"Hg
The month with the highest atmospheric pressure is January (30.1"Hg).
The months with the lowest atmospheric pressure are August and September (30.01"Hg).
Average wind speed in September
Forest Grove, OR
- Average wind speed in September: 4.1mph
The windiest month (with the highest average wind speed) is March (4.9mph).
The calmest month (with the lowest average wind speed) is August (4mph).
Average humidity in September
Forest Grove, OR
- Average humidity in September: 74%
The months with the highest relative humidity are February and December (88%).
The month with the lowest relative humidity is August (69%).
Average rainfall in September
Forest Grove, OR
- Average rainfall in September: 1.57"
The wettest month (with the highest rainfall) is January (5.47").
The driest months (with the least rainfall) are July and August (0.47").
Average rainfall days in September
Forest Grove, OR
- Average rainfall days in September: 11.4 days
The month with the highest number of rainy days is March (21.4 days).
The month with the least rainy days is August (6.2 days).
Average snowfall in September
Forest Grove, OR
- Average snowfall in September: 0"
The month with the highest snowfall is February (1.54").
The months with the least snowfall are April, May, June, July, August, September and October (0").
Average snowfall days in September
Forest Grove, OR
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is February (2.9 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
Forest Grove, OR
- Average daylight in September: 12h and 3min
The month with the longest days is June (Average daylight: 15h and 36min).
The month with the shortest days is December (Average daylight: 8h and 48min).
- Average sunshine in September: 8h and 4min
The month with the most sunshine is August (Average sunshine: 10h and 24min).
The months with the least sunshine are January and February (Average sunshine: 3h and 30min).
Average sunshine days in September
Forest Grove, OR
- Average sunshine days in September: 16.1 days
The month with the most sunshine days is August (22 days).
The month with the least sunshine days is March (7.6 days).
Average UV index in September
Forest Grove, OR
- Average UV index in September: 4
The months with the highest UV index are June and July (UV index 5).
The month with the lowest UV index is November (UV index 1).
Average cloud cover in September
Forest Grove, OR
- Average cloud cover in September: 39
The month with the most cloud cover is February (Cloud cover 66).
The month with the least cloud cover is August (Cloud cover 28).
Average visibility in September
Forest Grove, OR
- Average visibility in September: 5mi
The months with the highest visibility are July and August (6mi).
The months with the lowest visibility are January, February, March, November and December (4mi).
Forest Grove, Oregon, USA
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