September weather forecastTualatin, OR
September
Weather in September
September experiences a gentle decline in temperature, bringing relief from the oppressive summer heat. The change in climate is welcomed by farmers and gardeners alike, with rainfall levels gradually inching upwards to 1.57" (40mm). While the sharp summer sunshine softens to a more bearable extent, the extended daylight hours ensure plenty of time for outdoor activities. Before September draws to a close, there is noticeable withdrawal in daylight hours and dips in temperature. Moving towards the latter half of the year, anticipate a significant increase in rainfall and a further reduction in temperature.Temperature
September reveals a small adjustment in temperature, transitioning from an average high of 82°F (27.8°C) in August to a still warm 74.3°F (23.5°C). Compared to daytime temperatures, Tualatin's temperature drops significantly, averaging a cool 52°F (11.1°C) during the nights of September.Humidity
The average relative humidity in September is 69%.Rainfall
In Tualatin, during September, the rain falls for 10.8 days and regularly aggregates up to 1.57" (40mm) of precipitation. In Tualatin, during the entire year, the rain falls for 170.9 days and collects up to 30.67" (779mm) 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 the month, sunrise is at 6:33 am and sunset at 7:47 pm. On the last day of September, sunrise is at 7:09 am and sunset at 6:52 pm PDT.
Sunshine
In September, the average sunshine is 9.3h.UV index
In Tualatin, the average daily maximum UV index in September is 4. A UV Index estimate of 3 to 5 represents a moderate health risk from unsafe exposure to UV radiation for average individuals.Note: In September, the maximum UV index of 4 suggests this advice:
Act with care - Obligation to protect against skin and eye damage is highlighted. The Sun's most harmful UV rays are emitted around midday; avoid staying outdoors for long during this time. By wearing a generously brimmed hat, you can cut UV radiation exposure significantly.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Tualatin, OR
- Average high temperature in September: 74.3°F
The warmest month (with the highest average high temperature) is August (82°F).
The month with the lowest average high temperature is December (44.1°F).
- Average low temperature in September: 52°F
The month with the highest average low temperature is August (55°F).
The coldest month (with the lowest average low temperature) is December (34.5°F).
Average pressure in September
Tualatin, 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
Tualatin, OR
- Average wind speed in September: 4mph
The windiest month (with the highest average wind speed) is January (5.5mph).
The calmest month (with the lowest average wind speed) is August (3.9mph).
Average humidity in September
Tualatin, OR
- Average humidity in September: 69%
The months with the highest relative humidity are January, February and December (84%).
The month with the lowest relative humidity is August (63%).
Average rainfall in September
Tualatin, OR
- Average rainfall in September: 1.57"
The wettest month (with the highest rainfall) is December (4.57").
The driest month (with the least rainfall) is July (0.31").
Average rainfall days in September
Tualatin, OR
- Average rainfall days in September: 10.8 days
The month with the highest number of rainy days is March (19.8 days).
The month with the least rainy days is August (4.8 days).
Average snowfall in September
Tualatin, OR
- Average snowfall in September: 0"
The month with the highest snowfall is February (1.57").
The months with the least snowfall are April, May, June, July, August, September and October (0").
Average snowfall days in September
Tualatin, 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
Tualatin, 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 18min
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 6min).
Average sunshine days in September
Tualatin, OR
- Average sunshine days in September: 18 days
The month with the most sunshine days is July (25 days).
The month with the least sunshine days is February (8.6 days).
Average UV index in September
Tualatin, 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
Tualatin, OR
- Average cloud cover in September: 32
The month with the most cloud cover is February (Cloud cover 58).
The month with the least cloud cover is August (Cloud cover 22).
Average visibility in September
Tualatin, 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).
