Pittsboro climate

Pittsboro Frost Dates and Growing Season

NOAA 1991-2020 normals for Chatham Wtp, 15.8 km from Pittsboro, elevation 308 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Chatham Wtp. 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 1 and the first fall freeze around November 7, a growing season of about 221 days.

Median at 36°F
last April 12, first October 30
Median at 32°F
last April 1, first November 7
Median at 28°F
last March 21, first November 18

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 1Apr 23Apr 18Apr 15Apr 12Apr 8Apr 5Apr 1Mar 27
32°FApr 23Apr 14Apr 8Apr 4Apr 1Mar 29Mar 25Mar 21Mar 14
28°FApr 10Apr 2Mar 29Mar 25Mar 21Mar 17Mar 13Mar 8Mar 2
24°FMar 31Mar 22Mar 17Mar 13Mar 9Mar 6Mar 2Feb 27Feb 18
20°FMar 19Mar 12Mar 6Mar 1Feb 26Feb 21Feb 14Feb 6Jan 29
16°FMar 6Feb 27Feb 21Feb 13Feb 6Jan 31Jan 24Jan 15Jan 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 20Oct 23Oct 26Oct 28Oct 30Nov 1Nov 3Nov 6Nov 10
32°FOct 29Nov 1Nov 3Nov 5Nov 7Nov 9Nov 12Nov 16Nov 21
28°FNov 5Nov 9Nov 12Nov 15Nov 18Nov 21Nov 25Nov 30Dec 5
24°FNov 12Nov 17Nov 23Nov 27Dec 1Dec 4Dec 9Dec 16Dec 25
20°FNov 27Dec 2Dec 8Dec 12Dec 20Dec 25Jan 1Jan 8Jan 17
16°FDec 7Dec 16Dec 26Dec 30Jan 3Jan 10Jan 17Jan 24Feb 2

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°F222214210206201197193187180
32°F244236230226221217213208197
28°F270259252247242238233227219
24°F300289280275269263257249240
20°F332321311305299292285279268
16°F365355344335329321311305295

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
99% of years
16°F or colder
88% 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
3,351
Cooling degree days, base 65°F
1,703
Growing degree days, base 40°F
7,740
Growing degree days, base 45°F
6,220
Growing degree days, base 50°F
4,852
Growing degree days, base 55°F
3,646
Growing degree days, base 60°F
2,597

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January753024
February620038
March4547132
April18735313
May40162587
June2327776
July0477942
August1413877
September11231670
October16647354
November443296
December675142

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 15.8 km from Pittsboro. 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 USC00311700 (Chatham Wtp). Public domain.