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 sea temperature 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
September's arrival aligns with a minor decrease in average high-temperatures, from August's moderately hot 77.2°F (25.1°C) to an agreeable 70°F (21.1°C). During the month of September, an average low-temperature of 50.9°F (10.5°C) is recorded.Humidity
The average relative humidity in September is 75%.Rainfall
In Olalla, Washington, during September, the rain falls for 9.9 days and regularly aggregates up to 0.59" (15mm) of precipitation. In Olalla, during the entire year, the rain falls for 138.9 days and collects up to 12.24" (311mm) of precipitation.Snowfall
In Olalla, snow does not fall in April through October.Ocean temperature
The months with the warmest seawater in Olalla are August and September, with an average ocean temperature of 53.2°F (11.8°C).Note: Navigating the 53.2°F (11.8°C) at 55.4°F (13°C) is no joy, and temperatures less than 50°F (10°C) can threaten breathing and cause a chilling shock, gauging personal stamina.
Daylight
In September, the average length of the day is 12h and 32min.On the first day of September, sunrise is at 6:30 am and sunset at 7:49 pm. On the last day of the month, sunrise is at 7:08 am and sunset at 6:50 pm PDT.
Sunshine
The average sunshine in September is 9.3h.UV index
In September, the average daily maximum UV index in Olalla is 4. A UV Index estimate of 3 to 5 represents a medium vulnerability from exposure to the Sun's UV rays for ordinary individuals.Note: In September, the maximum UV index of 4 transforms into these recommendations:
Be vigilant - Suggestions to stave off sun damage are provided. It's recommended to limit sun exposure when its radiation is at its peak during midday. Tightly woven clothing, when worn loosely, shields effectively against the Sun.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What is the usual temperature for Olalla in September?
What is the average humidity in September in Olalla?
How many days does it rain in September in Olalla?
When it does not snow in Olalla?
What are the months with the warmest ocean in Olalla?
What is the water temperature in September in Olalla?
What is the average length of the day in September in Olalla?
When is the sunrise / sunset in September in Olalla?
How long on average sun shines in September in Olalla?
What is the UV index reading in September in Olalla?
Average temperature in September
Olalla, WA
- Average high temperature in September: 70°F
The warmest month (with the highest average high temperature) is August (77.2°F).
The month with the lowest average high temperature is December (43.2°F).
- Average low temperature in September: 50.9°F
The month with the highest average low temperature is August (53.6°F).
The coldest month (with the lowest average low temperature) is December (34.9°F).
Average pressure in September
Olalla, WA
- Average pressure in September: 30.01"Hg
The month with the highest atmospheric pressure is January (30.09"Hg).
The months with the lowest atmospheric pressure are March, August and September (30.01"Hg).
Average wind speed in September
Olalla, WA
- Average wind speed in September: 4.1mph
The windiest month (with the highest average wind speed) is March (5.5mph).
The calmest months (with the lowest average wind speed) are July and August (3.5mph).
Average humidity in September
Olalla, WA
- Average humidity in September: 75%
The month with the highest relative humidity is December (87%).
The month with the lowest relative humidity is July (69%).
Average rainfall in September
Olalla, WA
- Average rainfall in September: 0.59"
The wettest months (with the highest rainfall) are January and December (2.05").
The driest month (with the least rainfall) is July (0.28").
Average rainfall days in September
Olalla, WA
- Average rainfall days in September: 9.9 days
The month with the highest number of rainy days is March (15.3 days).
The month with the least rainy days is August (5.4 days).
Average snowfall in September
Olalla, WA
- Average snowfall in September: 0"
The month with the highest snowfall is February (1.22").
The months with the least snowfall are April, May, June, July, August, September and October (0").
Average snowfall days in September
Olalla, WA
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is February (2.8 days).
The months with the least snowfall days are May, June, July, August, September and October (0 days).
Average sea temperature in September
Olalla, WA
- Average sea temperature in September: 53.2°F
The best month for swimming (with the highest average sea temperature) is August (53.3°F).
The coldest month (with the lowest average sea temperature) is February (45.8°F).
Average daylight in September /
Average sunshine in September
Olalla, WA
- Average daylight in September: 12h and 3min
The month with the longest days is June (Average daylight: 15h and 54min).
The month with the shortest days is December (Average daylight: 8h and 30min).
- Average sunshine in September: 9h and 2min
The month with the most sunshine is August (Average sunshine: 10h and 42min).
The month with the least sunshine is December (Average sunshine: 4h and 6min).
Average sunshine days in September
Olalla, WA
- Average sunshine days in September: 18.5 days
The month with the most sunshine days is August (22.8 days).
The month with the least sunshine days is February (11.8 days).
Average UV index in September
Olalla, WA
- 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
Olalla, WA
- Average cloud cover in September: 34
The month with the most cloud cover is December (Cloud cover 58).
The month with the least cloud cover is August (Cloud cover 25).
Average visibility in September
Olalla, WA
- Average visibility in September: 6mi
The months with the highest visibility are May, June, July, August and September (6mi).
The months with the lowest visibility are January, February, March, April, October, November and December (5mi).
Olalla, Washington, USA
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