Varnamtown climate

Varnamtown Frost Dates and Growing Season

NOAA 1991-2020 normals for Shallotte Ag, 13 km from Varnamtown, elevation 20 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Shallotte Ag. 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 20 and the first fall freeze around November 17, a growing season of about 243 days.

Median at 36°F
last March 31, first November 6
Median at 32°F
last March 20, first November 17
Median at 28°F
last March 7, first December 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°FApr 14Apr 10Apr 6Apr 3Mar 31Mar 28Mar 25Mar 21Mar 17
32°FApr 4Mar 31Mar 27Mar 24Mar 20Mar 17Mar 14Mar 8Feb 28
28°FMar 26Mar 20Mar 16Mar 12Mar 7Mar 2Feb 26Feb 19Feb 5
24°FMar 15Mar 9Mar 3Feb 26Feb 19Feb 10Feb 2Jan 27Jan 14
20°FMar 3Feb 23Feb 13Feb 3Jan 29Jan 24Jan 18Jan 11Jan 2
16°FFeb 6Jan 31Jan 27Jan 22Jan 18Jan 14Jan 10Jan 5Dec 25

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 24Oct 30Nov 1Nov 4Nov 6Nov 9Nov 12Nov 15Nov 20
32°FNov 3Nov 7Nov 11Nov 14Nov 17Nov 21Nov 25Nov 30Dec 6
28°FNov 12Nov 19Nov 24Nov 28Dec 1Dec 5Dec 12Dec 22Jan 1
24°FNov 27Dec 3Dec 9Dec 16Dec 24Dec 31Jan 5Jan 12Jan 22
20°FDec 8Dec 18Dec 28Jan 2Jan 8Jan 13Jan 18Jan 26Feb 5
16°FDec 20Dec 31Jan 6Jan 10Jan 14Jan 17Jan 21Jan 27Feb 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°F246237231226222218214208201
32°F272262254249243239233227220
28°F307297288279273267259252241
24°F345333323314306298291281268
20°F365365358347339332322311298
16°F365365365365365365360345334

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
97% of years
20°F or colder
77% of years
16°F or colder
36% 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
2,429
Cooling degree days, base 65°F
1,865
Growing degree days, base 40°F
8,660
Growing degree days, base 45°F
6,988
Growing degree days, base 50°F
5,453
Growing degree days, base 55°F
4,073
Growing degree days, base 60°F
2,876

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January589068
February467177
March3338187
April12144378
May19172618
June1344793
July0470934
August0431896
September3292739
October8792472
November31210190
December499199

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 13 km from Varnamtown. 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 USC00317813 (Shallotte Ag). Public domain.