Grayson climate

Grayson Frost Dates and Growing Season

NOAA 1991-2020 normals for Columbia Lock, 13 km from Grayson, elevation 82 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Columbia Lock. 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 5 and the first fall freeze around November 22, a growing season of about 263 days.

Median at 36°F
last March 21, first November 10
Median at 32°F
last March 5, first November 22
Median at 28°F
last February 20, first December 4

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 7Apr 3Mar 30Mar 26Mar 21Mar 17Mar 12Mar 6Feb 28
32°FMar 27Mar 19Mar 14Mar 10Mar 5Mar 2Feb 27Feb 22Feb 14
28°FMar 14Mar 7Mar 2Feb 26Feb 20Feb 13Feb 6Jan 31Jan 20
24°FMar 5Feb 26Feb 14Feb 6Feb 1Jan 27Jan 20Jan 9Dec 31
20°FFeb 26Feb 5Feb 1Jan 27Jan 21Jan 14Jan 7Dec 31Dec 23
16°FFeb 12Feb 1Jan 26Jan 22Jan 17Jan 13Jan 7Dec 29Dec 20

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

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°F261253245240235230225219211
32°F289280273268263257251244235
28°F326314306299292284276269258
24°F365356343334328321312303292
20°F365365365365360351342333321
16°F365365365365365365365365348

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
90% of years
20°F or colder
52% of years
16°F or colder
16% 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
2,243
Cooling degree days, base 65°F
2,449
Growing degree days, base 40°F
9,421
Growing degree days, base 45°F
7,745
Growing degree days, base 50°F
6,196
Growing degree days, base 55°F
4,787
Growing degree days, base 60°F
3,531

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January565588
February4258113
March25729270
April9786443
May13270722
June0445895
July05471,012
August05421,007
September3361808
October80127513
November29521219
December5098104

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 Grayson. 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 USC00161979 (Columbia Lock). Public domain.