Fearrington climate

Fearrington Frost Dates and Growing Season

NOAA 1991-2020 normals for Chapel Hill 2 W, 11.3 km from Fearrington, elevation 500 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Chapel Hill 2 W. 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 March 31 and the first fall freeze around November 3, a growing season of about 218 days.

Median at 36°F
last April 14, first October 26
Median at 32°F
last March 31, first November 3
Median at 28°F
last March 19, first November 14

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°FApr 30Apr 24Apr 20Apr 18Apr 14Apr 11Apr 8Apr 4Mar 31
32°FApr 14Apr 8Apr 5Apr 2Mar 31Mar 28Mar 25Mar 21Mar 16
28°FApr 1Mar 29Mar 26Mar 22Mar 19Mar 15Mar 11Mar 7Mar 1
24°FMar 24Mar 17Mar 13Mar 8Mar 4Mar 1Feb 26Feb 19Feb 9
20°FMar 13Mar 6Mar 1Feb 23Feb 16Feb 10Feb 3Jan 30Jan 19
16°FMar 2Feb 19Feb 7Feb 2Jan 30Jan 24Jan 19Jan 11Jan 3

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 14Oct 18Oct 21Oct 24Oct 26Oct 28Oct 31Nov 2Nov 6
32°FOct 23Oct 27Oct 30Nov 1Nov 3Nov 5Nov 9Nov 13Nov 19
28°FNov 1Nov 5Nov 7Nov 11Nov 14Nov 17Nov 22Nov 27Dec 3
24°FNov 11Nov 17Nov 22Nov 27Dec 1Dec 4Dec 9Dec 17Dec 30
20°FNov 26Dec 2Dec 7Dec 12Dec 21Dec 27Jan 1Jan 8Jan 18
16°FDec 11Dec 20Dec 28Jan 1Jan 6Jan 11Jan 16Jan 22Feb 1

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°F214207202198195191187182175
32°F238231226222218214211206200
28°F268259252247242238233227220
24°F305292284278272265259252244
20°F336325317309303296290283271
16°F365363352343334329320311302

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
98% of years
16°F or colder
83% 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
3,500
Cooling degree days, base 65°F
1,605
Growing degree days, base 40°F
7,518
Growing degree days, base 45°F
6,015
Growing degree days, base 50°F
4,671
Growing degree days, base 55°F
3,489
Growing degree days, base 60°F
2,469

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January774025
February622034
March4757120
April21640295
May63139542
June5316760
July0446911
August0391856
September18218649
October18842331
November4575107
December682141

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 11.3 km from Fearrington. 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 USC00311677 (Chapel Hill 2 W). Public domain.