September weather forecastKeizer, OR
September
Weather in September
September hosts a shift from the warm summer climate to a cooler autumn atmosphere in Keizer, Oregon. It receives the first sign of significant rainfall since the onset of summer, standing at 1.22" (31mm). The breezy coolness of the upcoming fall makes its presence known. The once scorching summer sun becomes a gentle warmth, hinting at the start of autumn. The transition is smooth as the heat slowly dissipates and is replaced by the crisp fall weather.Temperature
September indicates a minor shift in the average high-temperature, from August's moderately hot 82°F (27.8°C) to a still warm 74.7°F (23.7°C). Keizer logs a substantial downturn to a cool 50.9°F (10.5°C) during September nights, a considerable shift from daytime highs.Humidity
In Keizer, the average relative humidity in September is 70%.Rainfall
In Keizer, during September, the rain falls for 8.9 days and regularly aggregates up to 1.22" (31mm) of precipitation. Throughout the year, there are 162.5 rainfall days, and 25.08" (637mm) 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 the month, sunrise is at 6:35 am and sunset at 7:48 pm. On the last day of September, sunrise is at 7:09 am and sunset at 6:53 pm PDT.
Sunshine
In Keizer, Oregon, the average sunshine in September is 9.4h.UV index
The average daily maximum UV index in September is 4. A UV Index reading of 3 to 5 represents a moderate threat to health from exposure to the Sun's UV rays for the average person.Note: In September, the maximum UV index of 4 suggests these recommendations:
Undertake protective steps - Preventing sun damage is advised. The Sun is at its harshest during midday; protect yourself by staying in shaded areas and minimizing exposure. To cut down UV radiation exposure by about half, sport a wide-brim hat.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Keizer, OR
- Average high temperature in September: 74.7°F
The warmest month (with the highest average high temperature) is August (82°F).
The month with the lowest average high temperature is December (45.5°F).
- Average low temperature in September: 50.9°F
The month with the highest average low temperature is August (54.1°F).
The coldest month (with the lowest average low temperature) is December (34.5°F).
Average pressure in September
Keizer, 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
Keizer, OR
- Average wind speed in September: 4.4mph
The windiest months (with the highest average wind speed) are January, March and November (5.5mph).
The calmest month (with the lowest average wind speed) is August (4.2mph).
Average humidity in September
Keizer, OR
- Average humidity in September: 70%
The months with the highest relative humidity are January, February and December (86%).
The month with the lowest relative humidity is August (65%).
Average rainfall in September
Keizer, OR
- Average rainfall in September: 1.22"
The wettest month (with the highest rainfall) is December (3.94").
The driest month (with the least rainfall) is July (0.28").
Average rainfall days in September
Keizer, OR
- Average rainfall days in September: 8.9 days
The month with the highest number of rainy days is March (19.6 days).
The month with the least rainy days is July (3.9 days).
Average snowfall in September
Keizer, OR
- Average snowfall in September: 0"
The month with the highest snowfall is February (1.18").
The months with the least snowfall are April, May, June, July, August, September and October (0").
Average snowfall days in September
Keizer, 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 April, May, June, July, August, September and October (0 days).
Average daylight in September /
Average sunshine in September
Keizer, OR
- Average daylight in September: 12h and 30min
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 24min
The month with the most sunshine is August (Average sunshine: 11h and 0min).
The month with the least sunshine is February (Average sunshine: 4h and 12min).
Average sunshine days in September
Keizer, OR
- Average sunshine days in September: 20 days
The month with the most sunshine days is July (26.3 days).
The month with the least sunshine days is March (8.8 days).
Average UV index in September
Keizer, 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
Keizer, OR
- Average cloud cover in September: 32
The month with the most cloud cover is February (Cloud cover 60).
The month with the least cloud cover is August (Cloud cover 21).
Average visibility in September
Keizer, OR
- Average visibility in September: 6mi
The months with the highest visibility are July, August and September (6mi).
The months with the lowest visibility are January, February, March, April, May, June, October, November and December (5mi).
