Forsyth County climate

Forsyth County Frost Dates and Growing Season

NOAA 1991-2020 normals for Winston Salem Rynlds AP, 3 km from Forsyth County, elevation 970 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Winston Salem Rynlds AP. 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 26 and the first fall freeze around November 9, a growing season of about 228 days.

Median at 36°F
last April 9, first October 30
Median at 32°F
last March 26, first November 9
Median at 28°F
last March 13, first November 23

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 27Apr 20Apr 16Apr 12Apr 9Apr 5Apr 2Mar 29Mar 23
32°FApr 11Apr 5Apr 2Mar 30Mar 26Mar 23Mar 18Mar 14Mar 6
28°FMar 30Mar 25Mar 20Mar 16Mar 13Mar 8Mar 3Feb 28Feb 21
24°FMar 19Mar 12Mar 7Mar 3Feb 27Feb 23Feb 17Feb 9Jan 31
20°FMar 9Mar 1Feb 24Feb 15Feb 8Feb 3Jan 29Jan 20Jan 11
16°FFeb 25Feb 14Feb 4Jan 31Jan 27Jan 22Jan 17Jan 10Jan 2

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 22Oct 25Oct 27Oct 30Nov 1Nov 3Nov 7Nov 12
32°FOct 28Oct 31Nov 3Nov 6Nov 9Nov 12Nov 15Nov 19Nov 26
28°FNov 5Nov 10Nov 14Nov 18Nov 23Nov 27Dec 1Dec 6Dec 14
24°FNov 19Nov 26Dec 2Dec 6Dec 11Dec 17Dec 23Dec 29Jan 5
20°FDec 5Dec 12Dec 21Dec 27Jan 1Jan 5Jan 11Jan 17Jan 27
16°FDec 19Dec 29Jan 2Jan 7Jan 12Jan 17Jan 22Jan 28Feb 8

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°F225218212208203198195190181
32°F253244238233228223219212205
28°F284273266260254249243237230
24°F321308301293287279271264254
20°F354343334327318311304297286
16°F365365362353344337331322310

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
72% 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
3,497
Cooling degree days, base 65°F
1,513
Growing degree days, base 40°F
7,430
Growing degree days, base 45°F
5,922
Growing degree days, base 50°F
4,578
Growing degree days, base 55°F
3,393
Growing degree days, base 60°F
2,374

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January783023
February617136
March4587126
April20639303
May58134541
June3308754
July0422887
August1373837
September23193619
October19235321
November464296
December694135

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 km from Forsyth County. 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 USW00093807 (Winston Salem Rynlds AP). Public domain.