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United States › Colorado › Douglas County › Climate Station CASTLE ROCK, CO US Distance 6 mi Normals 1991–2020

30-year climate normals

Douglas County Climate and Weather Averages

Hottest month — July

85.7°

average daily high. The coldest month is January, averaging a low of 18.0°F.

Douglas County gets 17.6" of precipitation a year and 57.5" of snow, and 40% of it falls in Jun, Jul, Aug.

Temperature through the year

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

20° 40° 60° 80° JanFebMarAprMayJunJulAugSepOctNovDec
MonthAvg highAvg low PrecipSnow
January 45.6° 18.0° 0.55" 8.0"
February 46.7° 19.9° 0.70" 10.7"
March 53.8° 26.5° 1.54" 10.7"
April 59.1° 32.5° 2.08" 8.3"
May 68.4° 41.6° 1.97" 1.1"
June 80.2° 50.5° 2.20" 0.0"
July 85.7° 56.4° 2.32" 0.0"
August 83.6° 54.7° 2.52" 0.0"
September 76.7° 46.6° 1.39" 0.4"
October 64.8° 34.6° 0.85" 2.7"
November 53.9° 25.7° 0.79" 6.7"
December 45.7° 18.0° 0.69" 8.9"

Rainfall by month

Precipitation is spread fairly evenly through the year here, with 40% falling in the wettest three months (Jun, Jul, Aug).

January 0.55"
February 0.70"
March 1.54"
April 2.08"
May 1.97"
June 2.20"
July 2.32"
August 2.52"
September 1.39"
October 0.85"
November 0.79"
December 0.69"
Annual total 17.6"

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 498
Heating degree days How much heating the climate demands 6,103
Approximate annual cooling cost At 16.16¢/kWh, Colorado average $80
Approximate annual electric heating cost Lower where heating is gas rather than electric $345

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 Douglas County, where electricity is one line of eight.

Common questions

What is the weather like in Douglas County?

Douglas County averages a high of 85.7°F in July and a low of 18.0°F in January. Annual precipitation is 17.6 inches, including 57.5 inches of snow.

When is the rainy season in Douglas County?

The wettest stretch is Jun, Jul, Aug, which accounts for 40% of the year's precipitation. Precipitation is relatively evenly distributed across the year.

How hot does it get in Douglas County?

The average daily high in July, the hottest month, is 85.7°F. That drives 498 cooling degree days a year, which is what your air conditioning has to work against.

Does it snow in Douglas County?

Yes. Douglas County averages 57.5 inches of snow a year.

Sources

  • Temperature, precipitation and snowfall normals — NOAA National Centers for Environmental Information, 1991–2020 Monthly Climate Normals, station CASTLE ROCK, CO US (USC00051401), 6 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, Colorado residential average.
  • Wet-season share is the wettest three consecutive months as a percentage of annual precipitation, calculated from the monthly normals.