September weather forecast
Olympia, WA

The calm Capitol Lake overlooking the Washington State Capitol building in Olympia, Washington
The calm Capitol Lake overlooking the Washington State Capitol building in Olympia, Washington

Weather in September

The first month of the autumn, September, is still a pleasant month in Olympia, Washington, with temperature in the range of an average low of 47.7°F (8.7°C) and an average high of 70.5°F (21.4°C).

Temperature

In Olympia, Washington, the average high-temperature in September marginally drops from a moderately hot 78.6°F (25.9°C) in August to an agreeable 70.5°F (21.4°C). In September, in Olympia, the average low-temperature is 47.7°F (8.7°C).

Humidity

The average relative humidity in September is 78%.

Rainfall

In September, the rain falls for 11.7 days. Throughout September, 1.81" (46mm) of precipitation is accumulated. In Olympia, during the entire year, the rain falls for 177.4 days and collects up to 37.05" (941mm) of precipitation.

Snowfall

In Olympia, Washington, snow does not fall in April through October.

Daylight

In Olympia, the average length of the day in September is 12h and 32min.
On the first day of September in Olympia, Washington, sunrise is at 6:31 am and sunset at 7:52 pm. On the last day of the month, sunrise is at 7:09 am and sunset at 6:53 pm PDT.

Sunshine

In Olympia, the average sunshine in September is 8.3h.

UV index

In September, the average daily maximum UV index in Olympia is 4. A UV Index of 3 to 5 symbolizes a medium vulnerability from exposure to the Sun's UV rays for the ordinary person.
Note: The daily maximum UV index of 4 in September interpret into the following advice:
Take precautions. Light skin individuals may get burned in less than 30 minutes. The Sun's most intense and consequently most harmful UV radiation during midday hours should be decreased by minimizing exposure and seeking shade. A wide-brim hat offers excellent sun protection for the eyes, ears, face, and neck. Sunglasses with UVA and UVB protection significantly reduce eye damage from sun exposure. Tightly woven, loose-fitting clothes provide additional protection from the Sun.
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FAQ

What is the temperature in September in Olympia?

The average high-temperature, in September, in Olympia, is 70.5°F (21.4°C), while the average low-temperature is 47.7°F (8.7°C).

What is the average humidity in September in Olympia?

In Olympia, Washington, the average relative humidity in September is 78%.

How many days does it rain in September in Olympia?

In Olympia, Washington, in September, it is raining for 11.7 days, with typically 1.81" (46mm) of accumulated precipitation.

When it does not snow in Olympia?

In Olympia, snow does not fall in April through October.

How many hours of daylight does Olympia have in September?

The average day length in September in Olympia, Washington, is 12h and 32min.

When are sunrise and sunset in September in Olympia?

On the first day of September in Olympia, sunrise is at 6:31 am and sunset at 7:52 pm. On the last day of the month, sunrise is at 7:09 am and sunset at 6:53 pm PDT.

How long on average sun shines in September in Olympia?

In September, the average sunshine duration in Olympia is 8.3h.

What is the UV index intensity in September in Olympia?

In Olympia, the average daily maximum UV index in September is 4. A UV Index value of 3 to 5 symbolizes a medium hazard to health from unsafe exposure to Sun's UV rays.
Average humidity
Average rainfall days
Average snowfall
Average snowfall days
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in September
Olympia, WA

Average temperature in September - Olympia, WA
  • Average high temperature in September: 70.5°F

The warmest month (with the highest average high temperature) is August (78.6°F).
The month with the lowest average high temperature is December (43°F).

  • Average low temperature in September: 47.7°F

The month with the highest average low temperature is August (50.5°F).
The coldest month (with the lowest average low temperature) is December (33.4°F).

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Average pressure in September
Olympia, WA

Average pressure in September - Olympia, WA
  • Average pressure in September: 30.02"Hg

The month with the highest atmospheric pressure is January (30.09"Hg).
The month with the lowest atmospheric pressure is March (30.01"Hg).

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Average wind speed in September
Olympia, WA

Average wind speed in September - Olympia, WA
  • Average wind speed in September: 3.8mph

The windiest months (with the highest average wind speed) are March and November (4.6mph).
The calmest month (with the lowest average wind speed) is September (3.8mph).

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Average humidity in September
Olympia, WA

Average humidity in September - Olympia, WA
  • Average humidity in September: 78%

The months with the highest relative humidity are January, November and December (89%).
The month with the lowest relative humidity is July (71%).

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Average rainfall in September
Olympia, WA

Average rainfall in September - Olympia, WA
  • Average rainfall in September: 1.81"

The wettest month (with the highest rainfall) is December (5.79").
The driest month (with the least rainfall) is July (0.39").

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Average rainfall days in September
Olympia, WA

Average rainfall days in September - Olympia, WA
  • Average rainfall days in September: 11.7 days

The month with the highest number of rainy days is March (20.4 days).
The month with the least rainy days is August (5.5 days).

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Average snowfall in September
Olympia, WA

Average snowfall in September - Olympia, WA
  • Average snowfall in September: 0"

The month with the highest snowfall is February (2.32").
The months with the least snowfall are April, May, June, July, August, September and October (0").

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Average snowfall days in September
Olympia, WA

Average snowfall days in September - Olympia, WA
  • Average snowfall days in September: 0 days

The month with the highest number of snowfall days is February (3.3 days).
The months with the least snowfall days are May, June, July, August, September and October (0 days).

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Average daylight in September /
Average sunshine in September
Olympia, WA

Average daylight in September / Average sunshine in September - Olympia, WA
  • Average daylight in September: 12h and 32min

The month with the longest days is June (Average daylight: 15h and 50min).
The month with the shortest days is December (Average daylight: 8h and 35min).

  • Average sunshine in September: 8h and 18min

The month with the most sunshine is August (Average sunshine: 10h and 12min).
The month with the least sunshine is December (Average sunshine: 3h and 24min).

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Average sunshine days in September
Olympia, WA

Average sunshine days in September - Olympia, WA
  • Average sunshine days in September: 16.1 days

The month with the most sunshine days is August (22.4 days).
The month with the least sunshine days is February (8.4 days).

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Average UV index in September
Olympia, WA

Average UV index in September - Olympia, WA
  • Average UV index in September: 4

The months with the highest UV index are June and July (UV index 5).
The months with the lowest UV index are January, February, November and December (UV index 2).

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Average cloud cover in September
Olympia, WA

Average cloud cover in September - Olympia, WA
  • Average cloud cover in September: 45

The months with the most cloud cover are January and December (Cloud cover 65).
The months with the least cloud cover are July and August (Cloud cover 35).

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Average visibility in September
Olympia, WA

Average visibility in September - Olympia, WA
  • Average visibility in September: 4mi

The months with the highest visibility are June, July and August (5mi).
The months with the lowest visibility are January, February, March, April, May, September, October, November and December (4mi).

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