Grayson County climate

Grayson County Frost Dates and Growing Season

NOAA 1991-2020 normals for Elk Creek 4SSW, 3.2 km from Grayson County, elevation 3439 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Elk Creek 4SSW. 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 16 and the first fall freeze around October 27, a growing season of about 193 days.

Median at 36°F
last April 28, first October 18
Median at 32°F
last April 16, first October 27
Median at 28°F
last April 5, first November 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°FMay 14May 8May 4May 1Apr 28Apr 24Apr 21Apr 18Apr 14
32°FMay 2Apr 27Apr 22Apr 19Apr 16Apr 14Apr 11Apr 7Apr 3
28°FApr 18Apr 14Apr 10Apr 7Apr 5Apr 2Mar 31Mar 28Mar 22
24°FApr 9Apr 5Apr 2Mar 30Mar 27Mar 25Mar 21Mar 18Mar 13
20°FApr 2Mar 29Mar 25Mar 21Mar 18Mar 15Mar 11Mar 6Feb 27
16°FMar 26Mar 20Mar 15Mar 12Mar 7Mar 3Feb 27Feb 18Feb 5

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 6Oct 11Oct 14Oct 16Oct 18Oct 21Oct 24Oct 27Oct 31
32°FOct 15Oct 19Oct 22Oct 25Oct 27Oct 29Nov 1Nov 4Nov 8
28°FOct 24Oct 28Oct 31Nov 2Nov 4Nov 7Nov 10Nov 14Nov 19
24°FNov 1Nov 5Nov 8Nov 11Nov 14Nov 17Nov 22Nov 27Dec 2
20°FNov 7Nov 13Nov 17Nov 22Nov 26Nov 30Dec 4Dec 9Dec 19
16°FNov 17Nov 25Dec 1Dec 3Dec 8Dec 14Dec 21Dec 27Jan 4

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°F191184180176172167163158151
32°F212206200196193189184179172
28°F233226221217213210205200194
24°F258249243238233229223218212
20°F285273266260255250244237230
16°F312301293286278272266258250

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
100% 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
5,175
Cooling degree days, base 65°F
474
Growing degree days, base 40°F
5,244
Growing degree days, base 45°F
3,944
Growing degree days, base 50°F
2,822
Growing degree days, base 55°F
1,875
Growing degree days, base 60°F
1,082

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,03307
February84407
March728022
April4101119
May16020329
June2389516
July2177640
August10134589
September9552409
October3642154
November620027
December88604

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 3.2 km from Grayson County. 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 USC00442730 (Elk Creek 4SSW). Public domain.