Norborne climate

Norborne Frost Dates and Growing Season

NOAA 1991-2020 normals for Carrollton, 17.4 km from Norborne, elevation 705 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Carrollton. 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 16 and the first fall freeze around October 23, a growing season of about 187 days.

Median at 36°F
last April 27, first October 12
Median at 32°F
last April 16, first October 23
Median at 28°F
last April 4, first November 1

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 9May 5May 1Apr 29Apr 27Apr 24Apr 21Apr 17Apr 13
32°FMay 1Apr 27Apr 23Apr 20Apr 16Apr 13Apr 10Apr 7Apr 1
28°FApr 21Apr 15Apr 11Apr 8Apr 4Apr 1Mar 30Mar 26Mar 19
24°FApr 9Apr 4Mar 31Mar 29Mar 26Mar 21Mar 18Mar 13Mar 7
20°FMar 31Mar 26Mar 21Mar 17Mar 14Mar 10Mar 7Mar 3Feb 27
16°FMar 22Mar 16Mar 12Mar 8Mar 6Mar 2Feb 28Feb 24Feb 18

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 28Oct 2Oct 6Oct 9Oct 12Oct 15Oct 17Oct 21Oct 25
32°FOct 7Oct 13Oct 17Oct 20Oct 23Oct 25Oct 27Oct 30Nov 3
28°FOct 19Oct 24Oct 28Oct 30Nov 1Nov 3Nov 6Nov 9Nov 14
24°FOct 31Nov 1Nov 5Nov 7Nov 9Nov 12Nov 16Nov 20Nov 26
20°FNov 6Nov 10Nov 13Nov 17Nov 20Nov 24Nov 28Dec 1Dec 7
16°FNov 11Nov 17Nov 23Nov 27Nov 30Dec 4Dec 8Dec 12Dec 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°F184180175171166162158153147
32°F207201196192187184179174166
28°F231223218213210205201196188
24°F253244239234229225221216207
20°F274266260254250245241234228
16°F294284279273268264257251243

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
5,336
Cooling degree days, base 65°F
1,254
Growing degree days, base 40°F
6,204
Growing degree days, base 45°F
4,956
Growing degree days, base 50°F
3,838
Growing degree days, base 55°F
2,849
Growing degree days, base 60°F
1,986

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,16801
February92806
March691154
April35712176
May11789441
June8266708
July1388852
August2333797
September62141531
October31422224
November670143
December1,01804

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 17.4 km from Norborne. Low ground, valleys and open fields freeze earlier and later than a town center or a hillside.

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Sources

NOAA NCEI U.S. Climate Normals, 1991-2020, annual and seasonal normals for station USC00231340 (Carrollton). Public domain.