30-year climate normals

Marion County Climate and Weather Averages

Hottest month — July

85.2°

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

Marion County gets 40.67" of precipitation a year, and 34% 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	36.4°	21.2°	2.59"
February	41.0°	24.0°	2.07"
March	52.1°	33.1°	3.28"
April	64.0°	43.1°	4.08"
May	73.8°	53.7°	4.32"
June	82.1°	63.0°	5.06"
July	85.2°	66.7°	4.29"
August	84.0°	64.7°	3.24"
September	78.1°	57.1°	2.57"
October	65.6°	45.4°	3.25"
November	52.0°	34.8°	3.25"
December	40.8°	26.2°	2.67"

Rainfall by month

Precipitation is spread fairly evenly through the year here, with 34% falling in the wettest three months (May, Jun, Jul).

January 2.59"

February 2.07"

March 3.28"

April 4.08"

May 4.32"

June 5.06"

July 4.29"

August 3.24"

September 2.57"

October 3.25"

November 3.25"

December 2.67"

Annual total 40.67"

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 1,127

Heating degree days How much heating the climate demands 5,221

Approximate annual cooling cost At 18.15¢/kWh, Indiana average $205

Approximate annual electric heating cost Lower where heating is gas rather than electric $332

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 Marion County, where electricity is one line of eight.

Common questions

What is the weather like in Marion County?

Marion County averages a high of 85.2°F in July and a low of 21.2°F in January. Annual precipitation is 40.67 inches, with essentially no snow.

When is the rainy season in Marion County?

The wettest stretch is May, Jun, Jul, which accounts for 34% of the year's precipitation. Precipitation is relatively evenly distributed across the year.

How hot does it get in Marion County?

The average daily high in July, the hottest month, is 85.2°F. That drives 1,127 cooling degree days a year, which is what your air conditioning has to work against.

Does it snow in Marion County?

Effectively no. Measurable snowfall is rare in Marion County.

Sources

Temperature, precipitation and snowfall normals — NOAA National Centers for Environmental Information, 1991–2020 Monthly Climate Normals, station INDIANAPOLIS EAGLE CREEK AP, IN US (USW00053842), 9 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, Indiana residential average.
Wet-season share is the wettest three consecutive months as a percentage of annual precipitation, calculated from the monthly normals.