Ocracoke climate

Ocracoke Frost Dates and Growing Season

NOAA 1991-2020 normals for Ocracoke, 1 km from Ocracoke, elevation 4 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Ocracoke. 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 1 and the first fall freeze around December 20, a growing season of about 293 days.

Median at 36°F
last March 16, first December 2
Median at 32°F
last March 1, first December 20
Median at 28°F
last February 8, first January 5

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 2Mar 29Mar 24Mar 20Mar 16Mar 12Mar 8Mar 4Feb 26
32°FMar 21Mar 14Mar 9Mar 5Mar 1Feb 26Feb 21Feb 14Feb 6
28°FMar 5Feb 27Feb 20Feb 14Feb 8Feb 3Jan 31Jan 26Jan 15
24°FFeb 20Feb 11Feb 4Jan 31Jan 28Jan 24Jan 19Jan 13Jan 6
20°FFeb 12Feb 3Jan 31Jan 27Jan 23Jan 19Jan 16Jan 11Jan 6
16°F–––––––––

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°FNov 14Nov 21Nov 25Nov 29Dec 2Dec 5Dec 10Dec 16Dec 26
32°FNov 29Dec 3Dec 9Dec 14Dec 20Dec 25Dec 31Jan 5Jan 14
28°FDec 11Dec 19Dec 27Jan 1Jan 5Jan 10Jan 15Jan 21Jan 30
24°FDec 22Jan 1Jan 5Jan 11Jan 15Jan 19Jan 23Jan 29Feb 5
20°FJan 3Jan 7Jan 12Jan 15Jan 19Jan 23Jan 27Jan 31Feb 6
16°F–––––––––

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°F290280273267262257252246238
32°F320310304299293288282274265
28°F353340334328322316311306296
24°F365365365358348339334328317
20°F365365365365365365365350335
16°F365365365365365365365365360

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
94% of years
24°F or colder
67% of years
20°F or colder
31% of years
16°F or colder
9% 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
2,508
Cooling degree days, base 65°F
1,829
Growing degree days, base 40°F
8,536
Growing degree days, base 45°F
6,866
Growing degree days, base 50°F
5,330
Growing degree days, base 55°F
3,976
Growing degree days, base 60°F
2,809

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January600160
February506050
March3963135
April15330332
May31144578
June1335784
July0457922
August0432897
September2305753
October67109508
November27511211
December4782101

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 1 km from Ocracoke. 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 USC00316349 (Ocracoke). Public domain.