Cost to Own
United States › Missouri › Jefferson County › Climate Station FESTUS, MO US Distance 8.1 mi Normals 1991–2020

30-year climate normals

Jefferson County Climate and Weather Averages

Hottest month — July

88.4°

average daily high. The coldest month is January, averaging a low of 22.3°F.

Jefferson County gets 43.57" of precipitation a year and 9.2" of snow, and 33% of it falls in Apr, May, Jun.

Temperature through the year

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

40° 60° 80° JanFebMarAprMayJunJulAugSepOctNovDec
MonthAvg highAvg low PrecipSnow
January 41.0° 22.3° 2.68" 2.1"
February 46.3° 25.3° 2.51" 2.7"
March 56.3° 33.6° 4.00" 1.1"
April 67.8° 43.8° 4.91" 0.2"
May 76.2° 53.8° 4.76" 0.0"
June 84.6° 62.6° 4.74" 0.0"
July 88.4° 67.2° 3.83" 0.0"
August 87.2° 65.4° 3.59" 0.0"
September 80.6° 57.1° 3.38" 0.0"
October 69.6° 45.5° 2.83" 0.0"
November 56.0° 35.1° 3.54" 0.6"
December 45.1° 26.5° 2.80" 2.5"

Rainfall by month

Precipitation is spread fairly evenly through the year here, with 33% falling in the wettest three months (Apr, May, Jun).

January 2.68"
February 2.51"
March 4.00"
April 4.91"
May 4.76"
June 4.74"
July 3.83"
August 3.59"
September 3.38"
October 2.83"
November 3.54"
December 2.80"
Annual total 43.57"

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 1,352
Heating degree days How much heating the climate demands 4,700
Approximate annual cooling cost At 13.68¢/kWh, Missouri average $185
Approximate annual electric heating cost Lower where heating is gas rather than electric $225

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 88.4°F in July and a low of 22.3°F in January. Annual precipitation is 43.57 inches, including 9.2 inches of snow.

When is the rainy season in Jefferson County?

The wettest stretch is Apr, May, Jun, which accounts for 33% of the year's precipitation. Precipitation is relatively evenly distributed across the year.

How hot does it get in Jefferson County?

The average daily high in July, the hottest month, is 88.4°F. That drives 1,352 cooling degree days a year, which is what your air conditioning has to work against.

Does it snow in Jefferson County?

Yes. Jefferson County averages 9.2 inches of snow a year.

Sources

  • Temperature, precipitation and snowfall normals — NOAA National Centers for Environmental Information, 1991–2020 Monthly Climate Normals, station FESTUS, MO US (USC00232850), 8.1 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, Missouri residential average.
  • Wet-season share is the wettest three consecutive months as a percentage of annual precipitation, calculated from the monthly normals.