Stonewall climate

Stonewall Frost Dates and Growing Season

NOAA 1991-2020 normals for Fredericksburg, 23.5 km from Stonewall, elevation 1685 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Fredericksburg. 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 18 and the first fall freeze around November 10, a growing season of about 235 days.

Median at 36°F
last April 3, first November 1
Median at 32°F
last March 18, first November 10
Median at 28°F
last March 4, first November 22

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 14Apr 11Apr 7Apr 3Apr 1Mar 27Mar 21Mar 13
32°FApr 9Apr 2Mar 28Mar 23Mar 18Mar 14Mar 10Mar 5Feb 27
28°FMar 24Mar 18Mar 13Mar 9Mar 4Mar 2Feb 26Feb 22Feb 13
24°FMar 14Mar 8Mar 3Feb 28Feb 22Feb 16Feb 9Feb 1Jan 22
20°FMar 5Feb 26Feb 18Feb 8Feb 1Jan 27Jan 19Jan 8Dec 27
16°FFeb 24Feb 11Feb 3Jan 28Jan 19Jan 10Jan 2Dec 26Dec 16

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 23Oct 26Oct 29Nov 1Nov 4Nov 6Nov 10Nov 15
32°FOct 27Nov 1Nov 4Nov 7Nov 10Nov 13Nov 17Nov 22Nov 28
28°FNov 2Nov 9Nov 13Nov 18Nov 22Nov 27Dec 1Dec 5Dec 11
24°FNov 14Nov 21Nov 27Dec 1Dec 5Dec 10Dec 16Dec 23Jan 1
20°FNov 28Dec 4Dec 10Dec 16Dec 23Dec 28Jan 2Jan 8Jan 24
16°FDec 6Dec 17Dec 24Dec 29Jan 1Jan 6Jan 14Feb 1Feb 11

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°F235227221216211206202196188
32°F261253246242235230225219211
28°F288277270265259254249243233
24°F328314304296289282274266256
20°F364349339331323315305296285
16°F365365365365360348339328316

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
91% of years
16°F or colder
57% 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
2,163
Cooling degree days, base 65°F
2,382
Growing degree days, base 40°F
9,433
Growing degree days, base 45°F
7,745
Growing degree days, base 50°F
6,171
Growing degree days, base 55°F
4,742
Growing degree days, base 60°F
3,477

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January559271
February3935123
March23527286
April83101472
May11267721
June0432882
July0529994
August0533998
September5335780
October77128520
November28920231
December512395

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 23.5 km from Stonewall. 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 USC00413329 (Fredericksburg). Public domain.