Ninety Six climate

Ninety Six Frost Dates and Growing Season

NOAA 1991-2020 normals for Greenwood 8NE, 8.7 km from Ninety Six, elevation 530 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Greenwood 8NE. 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 22 and the first fall freeze around November 13, a growing season of about 236 days.

Median at 36°F
last April 4, first November 3
Median at 32°F
last March 22, first November 13
Median at 28°F
last March 6, first November 26

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

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 23Oct 27Oct 30Nov 1Nov 3Nov 5Nov 8Nov 12Nov 17
32°FNov 1Nov 3Nov 6Nov 10Nov 13Nov 16Nov 20Nov 25Dec 1
28°FNov 8Nov 14Nov 18Nov 22Nov 26Dec 1Dec 4Dec 10Dec 23
24°FNov 21Nov 29Dec 3Dec 9Dec 18Dec 24Dec 30Jan 4Jan 13
20°FDec 6Dec 15Dec 24Dec 30Jan 3Jan 8Jan 14Jan 21Feb 1
16°FDec 21Dec 30Jan 3Jan 8Jan 12Jan 17Jan 21Jan 28Feb 5

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°F235227221217213209204200194
32°F263254248242236231227222214
28°F296285276270265259254247239
24°F334324314306299291284275263
20°F365358348337333325317305293
16°F365365365365363352343334320

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
99% of years
20°F or colder
85% of years
16°F or colder
49% 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
2,896
Cooling degree days, base 65°F
1,800
Growing degree days, base 40°F
8,174
Growing degree days, base 45°F
6,568
Growing degree days, base 50°F
5,118
Growing degree days, base 55°F
3,837
Growing degree days, base 60°F
2,732

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January671042
February531156
March37511167
April15740340
May39172598
June1352801
July0471936
August0423888
September8260702
October12264411
November3925125
December601153

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 8.7 km from Ninety Six. 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 USC00383758 (Greenwood 8NE). Public domain.