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 September's onset, the weather reveals a slight temperature decrease, transitioning from a moderately hot 81.1°F (27.3°C) in August to a still warm 73.6°F (23.1°C). West Linn reports a steady low-temperature average of 50.5°F (10.3°C) throughout September, revealing a large deviation from the daytime high.Humidity
In West Linn, the average relative humidity in September is 69%.Rainfall
In West Linn, during September, the rain falls for 9.5 days and regularly aggregates up to 1.5" (38mm) of precipitation. In West Linn, during the entire year, the rain falls for 169.9 days and collects up to 32.76" (832mm) of precipitation.Snowfall
April through October are months without snowfall.Daylight
In September, the average length of the day is 12h and 31min.On the first day of September, sunrise is at 6:33 am and sunset at 7:47 pm. On the last day of the month, sunrise is at 7:08 am and sunset at 6:51 pm PDT.
Sunshine
In West Linn, the average sunshine in September is 9.4h.UV index
The average daily maximum UV index in September in West Linn is 4. A UV Index of 3 to 5 symbolizes a medium vulnerability from unsafe exposure to UV radiation for ordinary individuals.Note: The maximum daily UV index, 4 in September, converts into the following recommendations:
Prioritize safety - Recommendations to avert sunburn are shared. UV radiation is strongest from the Sun during midday; protect yourself by staying in shaded areas. To mitigate harm from sun exposure, pick sunglasses offering UVA and UVB defense.
Published by: Weather Atlas | About Us
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?
When it does not snow?
What is the average length of the day in September in West Linn?
When are sunrise and sunset in September?
How many hours of sunshine does West Linn have in September?
What is the UV index reading in September?
Average temperature in September
West Linn, OR
- Average high temperature in September: 73.6°F
The warmest month (with the highest average high temperature) is August (81.1°F).
The month with the lowest average high temperature is December (44.4°F).
- Average low temperature in September: 50.5°F
The month with the highest average low temperature is August (54°F).
The coldest month (with the lowest average low temperature) is December (34.3°F).
Average pressure in September
West Linn, OR
- Average pressure in September: 30.01"Hg
The month with the highest atmospheric pressure is January (30.12"Hg).
The month with the lowest atmospheric pressure is August (30"Hg).
Average wind speed in September
West Linn, OR
- Average wind speed in September: 3.9mph
The windiest month (with the highest average wind speed) is January (6mph).
The calmest month (with the lowest average wind speed) is August (3.5mph).
Average humidity in September
West Linn, OR
- Average humidity in September: 69%
The month with the highest relative humidity is February (84%).
The month with the lowest relative humidity is August (64%).
Average rainfall in September
West Linn, OR
- Average rainfall in September: 1.5"
The wettest month (with the highest rainfall) is December (5.16").
The driest month (with the least rainfall) is July (0.24").
Average rainfall days in September
West Linn, OR
- Average rainfall days in September: 9.5 days
The month with the highest number of rainy days is March (20.3 days).
The month with the least rainy days is August (4 days).
Average snowfall in September
West Linn, OR
- Average snowfall in September: 0"
The month with the highest snowfall is February (1.5").
The months with the least snowfall are April, May, June, July, August, September and October (0").
Average snowfall days in September
West Linn, OR
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is February (2.3 days).
The months with the least snowfall days are April, May, June, July, August, September and October (0 days).
Average daylight in September /
Average sunshine in September
West Linn, 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: 9h and 2min
The month with the most sunshine is August (Average sunshine: 11h and 6min).
The month with the least sunshine is February (Average sunshine: 4h and 18min).
Average sunshine days in September
West Linn, OR
- Average sunshine days in September: 19 days
The month with the most sunshine days is July (26.2 days).
The month with the least sunshine days is February (8.1 days).
Average UV index in September
West Linn, OR
- Average UV index in September: 4
The month with the highest UV index is July (UV index 6).
The months with the lowest UV index are January, February, November and December (UV index 2).
Average cloud cover in September
West Linn, OR
- Average cloud cover in September: 32
The month with the most cloud cover is February (Cloud cover 57).
The month with the least cloud cover is August (Cloud cover 22).
Average visibility in September
West Linn, OR
- Average visibility in September: 6mi
The months with the highest visibility are July, August, September and October (6mi).
The months with the lowest visibility are January, February, March, April, May, June, November and December (5mi).
West Linn, Oregon, USA
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