30-year climate normals

Johnson County Climate and Weather Averages

Hottest month — July

87.5°

average daily high. The coldest month is January, averaging a low of 21.2°F.

Johnson County gets 37.74" of precipitation a year, and 39% of it falls in May, Jun, Jul.

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	38.7°	21.2°	1.06"
February	43.8°	25.3°	1.41"
March	55.1°	35.1°	2.27"
April	64.9°	44.8°	3.87"
May	73.9°	55.3°	5.38"
June	83.2°	64.9°	5.15"
July	87.5°	68.9°	4.22"
August	86.7°	67.3°	4.38"
September	78.1°	58.6°	3.54"
October	66.5°	46.9°	3.01"
November	53.1°	34.8°	2.03"
December	42.2°	25.4°	1.42"

Rainfall by month

Precipitation is spread fairly evenly through the year here, with 39% falling in the wettest three months (May, Jun, Jul).

January 1.06"

February 1.41"

March 2.27"

April 3.87"

May 5.38"

June 5.15"

July 4.22"

August 4.38"

September 3.54"

October 3.01"

November 2.03"

December 1.42"

Annual total 37.74"

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 1,351

Heating degree days How much heating the climate demands 4,926

Approximate annual cooling cost At 15.13¢/kWh, Kansas average $204

Approximate annual electric heating cost Lower where heating is gas rather than electric $261

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 Johnson County, where electricity is one line of eight.

Common questions

What is the weather like in Johnson County?

Johnson County averages a high of 87.5°F in July and a low of 21.2°F in January. Annual precipitation is 37.74 inches, with essentially no snow.

When is the rainy season in Johnson County?

The wettest stretch is May, Jun, Jul, which accounts for 39% of the year's precipitation. Precipitation is relatively evenly distributed across the year.

How hot does it get in Johnson County?

The average daily high in July, the hottest month, is 87.5°F. That drives 1,351 cooling degree days a year, which is what your air conditioning has to work against.

Does it snow in Johnson County?

Effectively no. Measurable snowfall is rare in Johnson County.

Sources

Temperature, precipitation and snowfall normals — NOAA National Centers for Environmental Information, 1991–2020 Monthly Climate Normals, station OLATHE JOHNSON CO EXEC AP, KS US (USW00003967), 5 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, Kansas residential average.
Wet-season share is the wettest three consecutive months as a percentage of annual precipitation, calculated from the monthly normals.