30-year climate normals

Jefferson County Climate and Weather Averages

Hottest month — August

69.7°

average daily high. The coldest month is February, averaging a low of 33.0°F.

Jefferson County gets 29.41" of precipitation a year, and 50% of it falls in Nov, Dec, Jan.

Temperature through the year

Each bar spans the average daily low to the average daily high for that month.

Month	Avg high	Avg low	Precip
January	45.3°	33.1°	4.29"
February	46.6°	33.0°	2.84"
March	49.8°	35.0°	2.94"
April	54.2°	38.8°	1.65"
May	59.5°	43.4°	1.17"
June	63.4°	47.4°	0.73"
July	68.2°	51.1°	0.46"
August	69.7°	51.1°	0.64"
September	66.1°	47.1°	1.29"
October	56.7°	41.6°	3.06"
November	49.4°	36.0°	5.11"
December	44.8°	33.4°	5.23"

Rainfall by month

Jefferson County has a distinct wet season. 50% of the year's precipitation arrives in Nov, Dec, Jan.

January 4.29"

February 2.84"

March 2.94"

April 1.65"

May 1.17"

June 0.73"

July 0.46"

August 0.64"

September 1.29"

October 3.06"

November 5.11"

December 5.23"

Annual total 29.41"

What this climate costs you

Degree days measure how hard a building has to work to stay comfortable. They are the reason two identical houses have very different power bills, and they are the link between the weather here and what you pay every month.

Cooling degree days How much air conditioning the climate demands 23

Heating degree days How much heating the climate demands 6,015

Approximate annual cooling cost At 14.95¢/kWh, Washington average $3

Approximate annual electric heating cost Lower where heating is gas rather than electric $315

These are rough planning figures from degree days and the state electricity price, not a bill estimate. House size, insulation and fuel type move them a lot. See the full cost of owning a home in Jefferson County, where electricity is one line of eight.

Common questions

What is the weather like in Jefferson County?

Jefferson County averages a high of 69.7°F in August and a low of 33.0°F in February. Annual precipitation is 29.41 inches, with essentially no snow.

When is the rainy season in Jefferson County?

The wettest stretch is Nov, Dec, Jan, which accounts for 50% of the year's precipitation. That is a pronounced wet season rather than rain spread evenly through the year.

How hot does it get in Jefferson County?

The average daily high in August, the hottest month, is 69.7°F. That drives 23 cooling degree days a year, which is what your air conditioning has to work against.

Does it snow in Jefferson County?

Effectively no. Measurable snowfall is rare in Jefferson County.

Sources

Temperature, precipitation and snowfall normals — NOAA National Centers for Environmental Information, 1991–2020 Monthly Climate Normals, station PORT ANGELES INTL AP, WA US (USW00094266), 21.8 miles from the county centroid.
Heating and cooling degree days — NOAA, same station and period.
Electricity price — US Energy Information Administration, Electric Power Monthly Table 5.6.A, Washington residential average.
Wet-season share is the wettest three consecutive months as a percentage of annual precipitation, calculated from the monthly normals.