September weather forecastCorvallis, OR
September
Weather in September
September brings a salient shift in Corvallis, Oregon's weather as summer transitions into fall. Along with falling temperatures, daylight hours begin to shorten and more cloud coverage is observed. Mild rain returns, marking the beginning of the wetter part of the year. Temperature highs descend to 73.4°F (23°C) indicating the recession of summer's warmth. The mix of sunny and overcast days creates varied and picturesque sky vistas, popular for seasonal photography.Temperature
The transition into September involves a small decrease in the average high-temperature, dipping slightly from a moderately hot 80.4°F (26.9°C) in August to a still warm 73.4°F (23°C). In Corvallis, the average temperature during the nights of September marks a significant drop from the daily high, settling at a frosty 48.6°F (9.2°C).Humidity
In Corvallis, the average relative humidity in September is 74%.Rainfall
In Corvallis, in September, during 9.3 rainfall days, 1.42" (36mm) of precipitation is typically accumulated. Throughout the year, there are 169.2 rainfall days, and 30.28" (769mm) of precipitation is accumulated.Snowfall
April through October are months without snowfall.Daylight
The average length of the day in September is 12h and 30min.On the first day of September, sunrise is at 6:36 am and sunset at 7:48 pm. On the last day of the month, sunrise is at 7:10 am and sunset at 6:54 pm PDT.
Sunshine
The average sunshine in September is 9h.UV index
In Corvallis, the average daily maximum UV index in September is 4. A UV Index value of 3 to 5 symbolizes a medium vulnerability from exposure to the Sun's UV rays for the ordinary person.Note: A maximum high UV index of 4 in September translates into the following recommendations:
Take necessary precautions - Suggestions to elude sunburn are provided. Limiting exposure to the direct Sun during midday hours can help prevent harmful UV radiation effects. Employ a hat with a wide brim for robust protection, cutting UV exposure by half.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Corvallis, OR
- Average high temperature in September: 73.4°F
The warmest month (with the highest average high temperature) is August (80.4°F).
The month with the lowest average high temperature is December (44.8°F).
- Average low temperature in September: 48.6°F
The month with the highest average low temperature is August (52°F).
The coldest month (with the lowest average low temperature) is December (34.2°F).
Average pressure in September
Corvallis, OR
- Average pressure in September: 30.01"Hg
The month with the highest atmospheric pressure is January (30.11"Hg).
The months with the lowest atmospheric pressure are August and September (30.01"Hg).
Average wind speed in September
Corvallis, OR
- Average wind speed in September: 3.9mph
The windiest month (with the highest average wind speed) is March (4.9mph).
The calmest month (with the lowest average wind speed) is September (3.9mph).
Average humidity in September
Corvallis, OR
- Average humidity in September: 74%
The month with the highest relative humidity is December (89%).
The month with the lowest relative humidity is August (69%).
Average rainfall in September
Corvallis, OR
- Average rainfall in September: 1.42"
The wettest month (with the highest rainfall) is December (4.8").
The driest month (with the least rainfall) is July (0.28").
Average rainfall days in September
Corvallis, OR
- Average rainfall days in September: 9.3 days
The month with the highest number of rainy days is March (20.9 days).
The month with the least rainy days is August (4.5 days).
Average snowfall in September
Corvallis, OR
- Average snowfall in September: 0"
The month with the highest snowfall is February (1.77").
The months with the least snowfall are April, May, June, July, August, September and October (0").
Average snowfall days in September
Corvallis, OR
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is February (1.8 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
Corvallis, OR
- Average daylight in September: 12h and 30min
The month with the longest days is June (Average daylight: 15h and 30min).
The month with the shortest days is December (Average daylight: 8h and 54min).
- Average sunshine in September: 9h and 0min
The months with the most sunshine are July and August (Average sunshine: 10h and 48min).
The month with the least sunshine is February (Average sunshine: 3h and 36min).
Average sunshine days in September
Corvallis, OR
- Average sunshine days in September: 19.3 days
The month with the most sunshine days is July (24.3 days).
The month with the least sunshine days is February (8.4 days).
Average UV index in September
Corvallis, OR
- Average UV index in September: 4
The months with the highest UV index are June, July and August (UV index 5).
The months with the lowest UV index are January, February, November and December (UV index 2).
Average cloud cover in September
Corvallis, OR
- Average cloud cover in September: 36
The month with the most cloud cover is February (Cloud cover 65).
The month with the least cloud cover is August (Cloud cover 25).
Average visibility in September
Corvallis, OR
- Average visibility in September: 5mi
The months with the highest visibility are June, July, August, September and October (5mi).
The months with the lowest visibility are January, February, March, April, May, November and December (4mi).
