McCormick climate

McCormick Frost Dates and Growing Season

NOAA 1991-2020 normals for Mccormick, 0.5 km from McCormick, elevation 507 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Mccormick. 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 28 and the first fall freeze around November 7, a growing season of about 226 days.

Median at 36°F
last April 7, first October 29
Median at 32°F
last March 28, first November 7
Median at 28°F
last March 16, first November 20

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 22Apr 18Apr 14Apr 10Apr 7Apr 5Apr 2Mar 30Mar 23
32°FApr 13Apr 6Apr 2Mar 31Mar 28Mar 25Mar 21Mar 17Mar 10
28°FApr 2Mar 28Mar 23Mar 19Mar 16Mar 11Mar 7Mar 1Feb 24
24°FMar 22Mar 16Mar 11Mar 6Mar 1Feb 25Feb 20Feb 14Feb 6
20°FMar 11Mar 3Feb 25Feb 19Feb 14Feb 8Feb 2Jan 26Jan 14
16°FFeb 28Feb 16Feb 8Feb 2Jan 30Jan 23Jan 16Jan 9Jan 1

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 17Oct 21Oct 24Oct 26Oct 29Oct 31Nov 1Nov 5Nov 10
32°FOct 25Oct 30Nov 1Nov 4Nov 7Nov 10Nov 14Nov 18Nov 28
28°FNov 4Nov 8Nov 12Nov 17Nov 20Nov 25Dec 1Dec 4Dec 11
24°FNov 16Nov 23Nov 30Dec 3Dec 7Dec 13Dec 21Dec 30Jan 6
20°FDec 1Dec 8Dec 16Dec 24Dec 31Jan 4Jan 9Jan 15Jan 28
16°FDec 16Dec 26Jan 1Jan 4Jan 9Jan 14Jan 20Jan 28Feb 9

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°F224216211207203200196191186
32°F252242236231226221216212204
28°F280271262256250246241234226
24°F312303296289283277270263252
20°F351335327320313307301292282
16°F365365364354344335328319306

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
95% of years
16°F or colder
70% 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
2,822
Cooling degree days, base 65°F
1,954
Growing degree days, base 40°F
8,396
Growing degree days, base 45°F
6,788
Growing degree days, base 50°F
5,330
Growing degree days, base 55°F
4,033
Growing degree days, base 60°F
2,904

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January645154
February527159
March36913174
April14449361
May32186618
June1382831
July0494959
August0468933
September7286729
October11567420
November3906132
December591159

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 0.5 km from McCormick. 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 USC00385660 (Mccormick). Public domain.