Williamsburg climate

Williamsburg Frost Dates and Growing Season

NOAA 1991-2020 normals for New York Cntrl Pk Twr, 7.3 km from Williamsburg, elevation 130 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for New York Cntrl Pk Twr. 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 30 and the first fall freeze around November 20, a growing season of about 236 days.

Median at 36°F
last April 7, first November 8
Median at 32°F
last March 30, first November 20
Median at 28°F
last March 19, 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 20Apr 16Apr 13Apr 9Apr 7Apr 5Apr 3Mar 31Mar 26
32°FApr 9Apr 5Apr 3Apr 1Mar 30Mar 27Mar 23Mar 19Mar 14
28°FApr 2Mar 29Mar 26Mar 22Mar 19Mar 16Mar 13Mar 10Mar 5
24°FMar 25Mar 19Mar 15Mar 12Mar 9Mar 7Mar 4Feb 28Feb 22
20°FMar 16Mar 11Mar 7Mar 4Mar 1Feb 26Feb 20Feb 14Feb 7
16°FMar 7Mar 1Feb 25Feb 20Feb 14Feb 8Feb 3Jan 30Jan 19

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 27Nov 1Nov 3Nov 5Nov 8Nov 11Nov 14Nov 18Nov 23
32°FNov 6Nov 10Nov 14Nov 17Nov 20Nov 23Nov 27Dec 1Dec 6
28°FNov 15Nov 21Nov 24Nov 28Dec 1Dec 4Dec 7Dec 11Dec 16
24°FNov 25Dec 1Dec 4Dec 9Dec 12Dec 16Dec 20Dec 25Jan 1
20°FDec 5Dec 12Dec 18Dec 22Dec 26Dec 30Jan 2Jan 7Jan 15
16°FDec 16Dec 23Dec 29Jan 2Jan 5Jan 8Jan 14Jan 20Jan 29

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°F234227222218215211207202196
32°F257250244240236232228223217
28°F279271265261257253247241236
24°F298291286282277272267262255
20°F322313306301298294289283276
16°F347335328324318312306301294

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
96% 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
4,553
Cooling degree days, base 65°F
1,222
Growing degree days, base 40°F
6,423
Growing degree days, base 45°F
5,062
Growing degree days, base 50°F
3,867
Growing degree days, base 55°F
2,829
Growing degree days, base 60°F
1,948

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January97004
February81606
March688134
April35414162
May12266410
June15226661
July0388852
August1345809
September32159578
October24022263
November511172
December804015

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 7.3 km from Williamsburg. 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 USW00094728 (New York Cntrl Pk Twr). Public domain.