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United States › Washington › Whatcom County › Climate Station DARRINGTON 21 NNE, WA US Distance 27.4 mi Normals 1991–2020

30-year climate normals

Whatcom County Climate and Weather Averages

Hottest month — August

77.8°

average daily high. The coldest month is February, averaging a low of 32.1°F.

Whatcom County gets 83" of precipitation a year, and 46% 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.

40° 60° JanFebMarAprMayJunJulAugSepOctNovDec
MonthAvg highAvg low Precip
January 42.1° 32.3° 12.84"
February 46.3° 32.1° 8.06"
March 51.2° 34.1° 8.74"
April 58.3° 38.5° 5.45"
May 66.2° 43.9° 3.53"
June 69.9° 48.5° 2.87"
July 77.1° 51.7° 1.58"
August 77.8° 51.8° 1.74"
September 70.9° 47.4° 3.99"
October 57.7° 41.0° 9.20"
November 46.8° 35.8° 13.72"
December 40.8° 32.2° 11.28"

Rainfall by month

Whatcom County has a distinct wet season. 46% of the year's precipitation arrives in Nov, Dec, Jan.

January 12.84"
February 8.06"
March 8.74"
April 5.45"
May 3.53"
June 2.87"
July 1.58"
August 1.74"
September 3.99"
October 9.20"
November 13.72"
December 11.28"
Annual total 83"

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 126
Heating degree days How much heating the climate demands 5,664
Approximate annual cooling cost At 14.95¢/kWh, Washington average $19
Approximate annual electric heating cost Lower where heating is gas rather than electric $296

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 Whatcom County, where electricity is one line of eight.

Common questions

What is the weather like in Whatcom County?

Whatcom County averages a high of 77.8°F in August and a low of 32.1°F in February. Annual precipitation is 83 inches, with essentially no snow.

When is the rainy season in Whatcom County?

The wettest stretch is Nov, Dec, Jan, which accounts for 46% 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 Whatcom County?

The average daily high in August, the hottest month, is 77.8°F. That drives 126 cooling degree days a year, which is what your air conditioning has to work against.

Does it snow in Whatcom County?

Effectively no. Measurable snowfall is rare in Whatcom County.

Sources

  • Temperature, precipitation and snowfall normals — NOAA National Centers for Environmental Information, 1991–2020 Monthly Climate Normals, station DARRINGTON 21 NNE, WA US (USW00004223), 27.4 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.