Santee climate

Santee Frost Dates and Growing Season

NOAA 1991-2020 normals for Holly Hill 1 Sw, 18.6 km from Santee, elevation 95 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Holly Hill 1 Sw. 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 12, a growing season of about 237 days.

Median at 36°F
last April 4, first November 3
Median at 32°F
last March 22, first November 12
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 19Apr 14Apr 11Apr 7Apr 4Apr 1Mar 29Mar 24Mar 18
32°FApr 6Apr 1Mar 30Mar 26Mar 22Mar 18Mar 14Mar 8Feb 28
28°FMar 27Mar 20Mar 16Mar 11Mar 6Mar 2Feb 25Feb 18Feb 6
24°FMar 14Mar 6Mar 1Feb 22Feb 13Feb 6Feb 1Jan 27Jan 15
20°FMar 1Feb 19Feb 9Feb 2Jan 29Jan 24Jan 17Jan 11Dec 31
16°FFeb 14Feb 2Jan 30Jan 27Jan 21Jan 16Jan 11Jan 5Dec 30

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 26Oct 30Nov 1Nov 3Nov 5Nov 8Nov 12Nov 18
32°FOct 31Nov 3Nov 6Nov 9Nov 12Nov 16Nov 19Nov 25Dec 2
28°FNov 8Nov 14Nov 17Nov 21Nov 26Dec 1Dec 4Dec 12Dec 24
24°FNov 21Nov 28Dec 4Dec 10Dec 17Dec 23Dec 31Jan 6Jan 16
20°FDec 6Dec 16Dec 25Dec 31Jan 4Jan 9Jan 15Jan 25Feb 5
16°FDec 20Dec 30Jan 2Jan 6Jan 11Jan 15Jan 23Jan 29Feb 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°F237229223218214210206201194
32°F264255248242237232227222214
28°F298287279272265260254246237
24°F336326317308302296288279266
20°F365361352343336330321311301
16°F365365365365365363352341330

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
97% of years
20°F or colder
79% of years
16°F or colder
40% 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
2,408
Cooling degree days, base 65°F
2,018
Growing degree days, base 40°F
8,829
Growing degree days, base 45°F
7,161
Growing degree days, base 50°F
5,628
Growing degree days, base 55°F
4,252
Growing degree days, base 60°F
3,047

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January580482
February452388
March31114215
April11257397
May21208653
June0387837
July0487952
August0463928
September4295741
October9186463
November32712178
December510496

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 18.6 km from Santee. 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 USC00384205 (Holly Hill 1 Sw). Public domain.