Castleberry climate

Castleberry Frost Dates and Growing Season

NOAA 1991-2020 normals for Evergreen Middleton Fld, 13.1 km from Castleberry, elevation 258 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Evergreen Middleton Fld. 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 10 and the first fall freeze around November 17, a growing season of about 251 days.

Median at 36°F
last March 28, first November 5
Median at 32°F
last March 10, first November 17
Median at 28°F
last February 22, 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 13Apr 7Apr 4Mar 31Mar 28Mar 24Mar 19Mar 14Mar 6
32°FMar 31Mar 24Mar 19Mar 14Mar 10Mar 5Feb 28Feb 24Feb 16
28°FMar 17Mar 10Mar 4Feb 28Feb 22Feb 17Feb 10Feb 2Jan 26
24°FMar 2Feb 22Feb 13Feb 7Feb 1Jan 29Jan 22Jan 15Jan 1
20°FFeb 13Feb 6Feb 1Jan 28Jan 22Jan 17Jan 11Jan 4Dec 28
16°FFeb 3Jan 31Jan 26Jan 19Jan 16Jan 11Jan 7Jan 2Dec 29

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 22Oct 27Nov 1Nov 3Nov 5Nov 8Nov 11Nov 15Nov 22
32°FNov 1Nov 6Nov 10Nov 13Nov 17Nov 21Nov 25Nov 30Dec 6
28°FNov 11Nov 17Nov 22Nov 27Dec 1Dec 6Dec 13Dec 26Jan 3
24°FNov 25Dec 2Dec 10Dec 20Dec 30Jan 2Jan 8Jan 15Jan 29
20°FDec 10Dec 26Jan 1Jan 4Jan 9Jan 13Jan 19Jan 29Feb 4
16°FDec 26Dec 31Jan 3Jan 8Jan 12Jan 16Jan 20Jan 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°F252241234229224219214209202
32°F283272265258251246240232223
28°F321309301291286277270262253
24°F364347338330323315306296284
20°F365365365365357346337330317
16°F365365365365365365365360340

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
91% of years
20°F or colder
58% of years
16°F or colder
23% 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
1,762
Cooling degree days, base 65°F
2,606
Growing degree days, base 40°F
10,005
Growing degree days, base 45°F
8,256
Growing degree days, base 50°F
6,617
Growing degree days, base 55°F
5,119
Growing degree days, base 60°F
3,774

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January46310132
February32217169
March19046334
April66104489
May7294752
June0462912
July05461,011
August0533998
September2394843
October58157565
November24630256
December40914157

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 13.1 km from Castleberry. 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 USW00053820 (Evergreen Middleton Fld). Public domain.