Knightsville climate

Knightsville Frost Dates and Growing Season

NOAA 1991-2020 normals for Terre Haute Caa AP, 18.2 km from Knightsville, elevation 575 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Terre Haute Caa AP. 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 14 and the first fall freeze around October 24, a growing season of about 192 days.

Median at 36°F
last April 25, first October 12
Median at 32°F
last April 14, first October 24
Median at 28°F
last April 2, first November 4

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 14May 7May 2Apr 29Apr 25Apr 23Apr 19Apr 16Apr 11
32°FMay 2Apr 25Apr 21Apr 17Apr 14Apr 11Apr 7Apr 4Mar 31
28°FApr 18Apr 12Apr 7Apr 5Apr 2Mar 31Mar 28Mar 23Mar 16
24°FApr 6Apr 2Mar 30Mar 26Mar 22Mar 19Mar 15Mar 10Mar 4
20°FMar 30Mar 23Mar 19Mar 16Mar 12Mar 8Mar 4Feb 28Feb 22
16°FMar 20Mar 14Mar 9Mar 6Mar 2Feb 28Feb 24Feb 18Feb 11

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 25Oct 1Oct 5Oct 9Oct 12Oct 14Oct 18Oct 21Oct 26
32°FOct 7Oct 15Oct 20Oct 22Oct 24Oct 27Oct 29Nov 1Nov 6
28°FOct 23Oct 28Oct 31Nov 2Nov 4Nov 7Nov 10Nov 14Nov 20
24°FNov 3Nov 6Nov 9Nov 12Nov 15Nov 19Nov 22Nov 28Dec 4
20°FNov 9Nov 15Nov 19Nov 23Nov 26Dec 1Dec 4Dec 9Dec 17
16°FNov 17Nov 24Nov 28Dec 2Dec 6Dec 10Dec 16Dec 20Dec 25

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°F188182177173168163160154145
32°F212206200196192188183177168
28°F237229224220216212207201194
24°F264255249243238234229224216
20°F285276269264259254248242235
16°F305295289284279274268261252

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
5,089
Cooling degree days, base 65°F
1,045
Growing degree days, base 40°F
5,966
Growing degree days, base 45°F
4,716
Growing degree days, base 50°F
3,588
Growing degree days, base 55°F
2,599
Growing degree days, base 60°F
1,767

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,11500
February90201
March694017
April3273155
May7458450
June1243691
July0324788
August0285749
September57118512
October30914192
November649033
December96100

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 18.2 km from Knightsville. 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 USW00093823 (Terre Haute Caa AP). Public domain.