Burns Harbor climate

Burns Harbor Frost Dates and Growing Season

NOAA 1991-2020 normals for Indiana Dunes Nl, 3.8 km from Burns Harbor, elevation 680 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Indiana Dunes Nl. 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 April 22 and the first fall freeze around October 27, a growing season of about 188 days.

Median at 36°F
last May 4, first October 16
Median at 32°F
last April 22, first October 27
Median at 28°F
last April 8, first November 7

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°FMay 21May 15May 11May 7May 4May 1Apr 29Apr 25Apr 20
32°FMay 8May 2Apr 29Apr 25Apr 22Apr 19Apr 16Apr 12Apr 7
28°FApr 23Apr 18Apr 14Apr 11Apr 8Apr 5Apr 2Mar 31Mar 26
24°FApr 12Apr 6Apr 3Mar 31Mar 29Mar 26Mar 23Mar 18Mar 12
20°FMar 31Mar 27Mar 24Mar 20Mar 17Mar 13Mar 10Mar 6Mar 1
16°FMar 23Mar 17Mar 13Mar 9Mar 6Mar 3Mar 1Feb 25Feb 17

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°FOct 4Oct 8Oct 11Oct 14Oct 16Oct 19Oct 22Oct 25Oct 30
32°FOct 15Oct 20Oct 22Oct 25Oct 27Oct 30Nov 1Nov 4Nov 9
28°FOct 26Oct 31Nov 2Nov 4Nov 7Nov 10Nov 14Nov 18Nov 25
24°FNov 4Nov 8Nov 12Nov 15Nov 19Nov 22Nov 26Dec 1Dec 5
20°FNov 11Nov 17Nov 23Nov 26Nov 30Dec 1Dec 6Dec 10Dec 16
16°FNov 21Nov 28Dec 1Dec 5Dec 8Dec 11Dec 16Dec 20Dec 24

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°F184177171167164160155150143
32°F209203197192188184180175167
28°F234227222218213208204200192
24°F258252246241236231227220213
20°F280273265260256252247242234
16°F301291285279275271265259251

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
6,171
Cooling degree days, base 65°F
808
Growing degree days, base 40°F
5,208
Growing degree days, base 45°F
4,056
Growing degree days, base 50°F
3,043
Growing degree days, base 55°F
2,160
Growing degree days, base 60°F
1,414

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,24201
February1,02802
March848228
April5067100
May24054304
June56161556
July8255711
August11214668
September93102461
October37114175
November707033
December1,06203

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 3.8 km from Burns Harbor. 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 USC00124244 (Indiana Dunes Nl). Public domain.