Climate · Jefferson

Jefferson, IN climate

Jefferson has chilly winters and pleasant summers. A typical July afternoon reaches 83°, a January night drops to 18°, and about 18 inches of snow falls in a normal winter.

NOAA 1991-2020 climate normals Updated once a decade
July high
83°
236th coolest of 1,978 Indiana towns
January low
18°
662nd coldest of 1,978 Indiana towns
Rain + melted snow
42 in
917th driest of 1,978 Indiana towns
Snow a winter
18 in
821st least snowy of 1,972 Indiana towns
A normal year

What a year in Jefferson feels like

Winter

37° / 21°
Typical high / low · 6 days with an inch or more of snow

Spring

61° / 40°
Typical high / low · Last frost around Apr 23

Summer

82° / 61°
Typical high / low · 11 days reach 90° in a normal year

Fall

64° / 43°
Typical high / low · First frost around Oct 19
Best months to be outsideMayJunJulAugSepOctHighs of 62–84° and lows of 40° or more
Month by month

Jefferson weather by month

Average highs, lows, rain and snow for every month, from NOAA’s 1991–2020 normals.

MonthHighLowRain + meltSnowWet daysSnow on ground30-yr range
January34°18°2.8" 5.5"119 18° – 38°
February39°21°2.3" 4.2"108 17° – 41°
March50°30°3.1" 2.2"111 33° – 55°
April62°40°4.2" 0.2"120 44° – 56°
May73°51°4.6" 0130 55° – 70°
June81°60°4.9" 0120 66° – 73°
July83°63°4.5" 0100 67° – 80°
August82°61°3.5" 090 67° – 78°
September77°53°3.1" 080 60° – 70°
October65°43°3.3" 0100 50° – 59°
November50°33°3.4" 0.7"100 34° – 49°
December38°24°2.8" 5.3"116 17° – 41°
Year61°41°42.4"18.1"12524

“Wet days” have at least 0.01" of rain or melted snow. “Snow on ground” counts days with 1" or more. The 30-year range is the coldest and warmest that month’s average temperature got between 1991 and 2020.

Rain & snow

Rain and snow in Jefferson

Jefferson gets 42 inches of rain and melted snow a year. June is the wettest month and February the driest. Rain or snow falls on about 125 days a year. Snow covers the ground about 24 days of the year.

42 in
Rain + melted snow a year
More rain than 60% of U.S. towns
18 in
Snow in a normal winter
Less snow than 60% of U.S. towns
24 days
With 1"+ of snow on the ground
Fewer than 54% of U.S. towns

Rain + melted snow by month

Inches of water
4.9"

Snowfall by month

Inches of snow
5.5"
Frost & the growing season

About 178 frost-free days a year

In half of years the last 32° night comes by April 23 and the first one by October 19. That leaves about 178 frost-free days for gardens, longer than 50% of U.S. towns.

127
nights at or below 32° in a normal year
7
nights below 0° in a normal year
11
days that reach 90° in a normal year

Freezing nights by month

Average nights at or below 32°

90° days by month

Average days at 90° or more
Heating & cooling

Heating and cooling a home in Jefferson

Engineers use “degree days” to estimate how hard a furnace or air conditioner works. In Jefferson, 87% of that work is heating and 13% is cooling, so the furnace matters far more than the air conditioner.

87%heating
5,850 heating degree daysMore heating than 52% of U.S. towns
840 cooling degree daysMore cooling than 50% of U.S. towns

Degree days measure how far each day’s average temperature falls below or rises above 65°, added up over a year. Source: NOAA station normals.

Around Jefferson

Jefferson and its neighbors

Jefferson borders 6 towns with climate data. January nights across them vary by 0.2°. Center has the coldest January nights (18°) and Franklin the hottest July afternoons (84°). Jefferson’s January low is 18° and its July high 83°.

Harrison: January low 18°, July high 83°Eel River: January low 19°, July high 83°Walnut: January low 18°, July high 84°Clark: January low 19°, July high 84°Union: January low 18°, July high 83°Sugar Creek: January low 18°, July high 84°Union: January low 18°, July high 84°Zionsville: January low 19°, July high 84°Clinton: January low 18°, July high 83°Perry: January low 19°, July high 83°Worth: January low 18°, July high 84°Marion: January low 18°, July high 83°Perry: January low 18°, July high 83°Whitestown: January low 19°, July high 84°Jackson: January low 18°, July high 83°Jackson: January low 18°, July high 83°Franklin: January low 18°, July high 84°Center: January low 18°, July high 83°Sugar Creek: January low 18°, July high 84°Lebanon: January low 18°, July high 83°Washington: January low 18°, July high 83°Jefferson: January low 18°, July high 83° JeffersonJacksonFranklinCenterSugar CreekLebanonWashington
ColderMilder18° to 19°
Center18.1° −0.1°
Sugar Creek18.1° −0.1°
Washington18.1° −0.1°
Jefferson18.2°
Franklin18.2° same
Jackson18.3° +0.1°
Lebanon18.3° +0.1°

Temperatures and rain come from NOAA’s 5 km grid, so each town gets its own value.

Compared with other towns

How Jefferson compares

Summer heat83° July high
Cooler than 63% of U.S. towns236th coolest of 1,978 Indiana towns
Winter cold18° January low
Colder than 55% of U.S. towns662nd coldest of 1,978 Indiana towns
Precipitation42" a year
Wetter than 60% of U.S. towns917th driest of 1,978 Indiana towns
Snow18" a winter
Less snow than 60% of U.S. towns821st least snowy of 1,972 Indiana towns
Growing season178 frost-free days
Longer than 50% of U.S. towns814th shortest of 1,978 Indiana towns

Compared with every U.S. town and city on TownTapestry, each counted once.

Then and now

Warmer than it used to be

+1.1°1991–2020 average vs. the 20th century (1901–2000)

The last 30 years in Jefferson averaged 1.1° warmer than the 1900s. The biggest change is in December (+2.3°). The shift is smaller than in 59% of U.S. towns.

❄️ Winter+1.7° now 29°, was 27°
🌷 Spring+1.6° now 51°, was 49°
☀️ Summer+0.2° now 72°, was 71°
🍂 Fall+1.1° now 53°, was 52°

Change by month1991–2020 average minus 1901–2000 average, at Jefferson’s spot on NOAA’s grid

Year to year

How much a month can swing

A normal is an average, and real years wander around it. February swings the most: between 1991 and 2020 its average temperature ranged from 17° to 41°. June is the most reliable, staying within 7°.

Coldest to warmest month in 30 yearsNormal
Questions

Common questions about Jefferson’s climate

What is the coldest month in Jefferson?

January, with a typical high of 34° and a low of 18°.

What is the hottest month in Jefferson?

July, with a typical high of 83° and a low of 63°. About 11 days a year reach 90°.

How much snow does Jefferson get?

About 18 inches in a normal winter, most of it in January.

When is the first frost in Jefferson?

In half of years the first 32° night comes by October 19, and the last spring frost by April 23.

What is the rainiest month in Jefferson?

June, with 4.9 inches of rain and melted snow. The year totals 42 inches.

Temperatures and rainfall come from NOAA’s gridded climate normals for Jefferson itself (about a 3-mile square). Snow, frost dates and day counts come from NOAA’s weather station at Lebanon 6w, IN (3 mi, snow) and Jamestown 2 E, IN (9 mi, frost, heat and degree days). Normals are 30-year averages, not a forecast. Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000.

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