Indiana climate

Indiana Frost Dates and Growing Season

NOAA 1991-2020 normals for Indiana 3 Se, 3.9 km from Indiana, elevation 1102 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Indiana 3 Se. A median date has an even chance of a later freeze in spring, or an earlier one in fall.

The last spring freeze typically comes around May 8 and the first fall freeze around October 13, a growing season of about 157 days.

Median at 36°F
last May 20, first October 3
Median at 32°F
last May 8, first October 13
Median at 28°F
last April 27, first October 25

Last freeze in spring

The chance of a later freeze than the date shown. At 10 percent, one spring in ten still freezes after the date; planting after the 10 percent date for 32°F is the cautious choice.

Threshold10%20%30%40%50%60%70%80%90%
36°FJun 2May 30May 26May 23May 20May 17May 13May 9May 4
32°FMay 24May 19May 15May 11May 8May 5May 1Apr 28Apr 23
28°FMay 14May 7May 3Apr 30Apr 27Apr 24Apr 21Apr 18Apr 13
24°FApr 30Apr 24Apr 20Apr 17Apr 15Apr 11Apr 9Apr 5Mar 30
20°FApr 16Apr 11Apr 8Apr 5Apr 3Mar 31Mar 29Mar 24Mar 18
16°FApr 4Apr 1Mar 29Mar 25Mar 22Mar 19Mar 16Mar 11Mar 5

First freeze in fall

The chance of an earlier freeze than the date shown. At 10 percent, one fall in ten freezes before the date.

Threshold10%20%30%40%50%60%70%80%90%
36°FSep 19Sep 24Sep 27Sep 30Oct 3Oct 5Oct 8Oct 11Oct 15
32°FOct 1Oct 5Oct 7Oct 10Oct 13Oct 16Oct 19Oct 23Oct 27
28°FOct 9Oct 15Oct 19Oct 22Oct 25Oct 28Oct 31Nov 3Nov 7
24°FOct 21Oct 27Oct 31Nov 2Nov 5Nov 8Nov 10Nov 14Nov 19
20°FNov 2Nov 6Nov 10Nov 12Nov 15Nov 18Nov 22Nov 26Dec 2
16°FNov 10Nov 15Nov 19Nov 23Nov 27Nov 30Dec 4Dec 8Dec 18

Growing season length

Days between the last spring and first fall freeze at each threshold, with the chance of a season at least that long.

Threshold10%20%30%40%50%60%70%80%90%
36°F155148143139135131127123117
32°F178171166161157153148143136
28°F201194188184180176171166160
24°F225219213210205200196191184
20°F247240235231227223218214208
16°F277267260255250244240234226

How often it gets that cold

The share of years with at least one night at or below each temperature.

36°F or colder
100% of years
32°F or colder
100% of years
28°F or colder
100% of years
24°F or colder
100% of years
20°F or colder
100% of years
16°F or colder
100% of years

Degree days

A degree day is one degree of the daily mean temperature beyond a base, for one day. Heating degree days count cold (the fuel a house burns), cooling degree days heat, growing degree days the warmth a crop needs; each crop has its own base.

Heating degree days, base 65°F
6,147
Cooling degree days, base 65°F
528
Growing degree days, base 40°F
4,875
Growing degree days, base 45°F
3,717
Growing degree days, base 50°F
2,703
Growing degree days, base 55°F
1,827
Growing degree days, base 60°F
1,092

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,18702
February1,01402
March865019
April503292
May22329292
June5399497
July9184640
August16153601
September11454393
October4147138
November735023
December1,01404

What this means

NOAA computes these from the daily lows at the station over 1991-2020, fitting the dates of each year's last and first freeze to a distribution, so a date can be stated at any level of risk. 36°F is a frost risk for tender plants on a clear, calm night, since the ground cools below the air above it; 32°F is a freeze; 28°F is a hard freeze that kills most annuals.

The station is 3.9 km from Indiana. Low ground, valleys and open fields freeze earlier and later than a town center or a hillside.

More

Sources

NOAA NCEI U.S. Climate Normals, 1991-2020, annual and seasonal normals for station USC00364214 (Indiana 3 Se). Public domain.