September weather forecast and climate
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

What is the temperature in September in Olympia?

In September, the average high-temperature is 71.8°F (22.1°C), and the average low-temperature is 46°F (7.8°C).

How many days does it rain in September in Olympia?

In Olympia, during September, the rain falls for 7.8 days and regularly aggregates up to 1.7" (43.4mm) of precipitation.
Average temperature in September - Olympia, WA
  • Average high temperature in September: 22.1°C

The warmest month (with the highest average high temperature) is August (25.4°C).
The month with the lowest average high temperature is December (6.8°C).

  • Average low temperature in September: 7.8°C

The month with the highest average low temperature is July (10.4°C).
The coldest month (with the lowest average low temperature) is December (0.3°C).

Average humidity in September - Olympia, WA
  • Average humidity in September: 77.6%

The month with the highest relative humidity is December (89.1%).
The month with the lowest relative humidity is July (70.8%).

Average rainfall in September - Olympia, WA
  • Average rainfall in September: 43.4mm

The wettest month (with the highest rainfall) is November (219.2mm).
The driest month (with the lowest rainfall) is July (16mm).

Average rainfall days in September - Olympia, WA
  • Average rainfall days in September: 7.8 days

The month with the highest number of rainy days is November (20.1 days).
The month with the lowest number of rainy days is July (4.6 days).

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

The month with the highest snowfall is February (119.4mm).
Months with the lowest snowfall are April, May, June, July, August, September and October (0mm).

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 (2.2 days).
Months with the lowest number of snowfall days are May, June, July, August, September and October (0 days).

Average daylight in September / Average sunshine in September - Olympia, WA
  • Average daylight in September: 12.5h

The month with the longest days is June (Average daylight: 15.8h).
The month with shortest days is December (Average daylight: 8.6h).

  • Average sunshine in September: 7h

The month with most sunshine is July (Average sunshine: 10h).
Months with least sunshine are January and December (Average sunshine: 2).

Average UV index in September - Olympia, WA
  • Average UV index in September: 5

Months with the highest UV index are June, July and August (UV index 7).
Months with the lowest UV index are January, November and December (UV index 1).

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