Columbia County climate

Columbia County Frost Dates and Growing Season

NOAA 1991-2020 normals for Clarks Hill 1 W, 14.9 km from Columbia County, elevation 400 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Clarks Hill 1 W. 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 15 and the first fall freeze around November 18, a growing season of about 252 days.

Median at 36°F
last March 29, first November 6
Median at 32°F
last March 15, first November 18
Median at 28°F
last February 26, first December 8

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

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 26Oct 31Nov 2Nov 4Nov 6Nov 9Nov 12Nov 16Nov 22
32°FNov 3Nov 8Nov 11Nov 15Nov 18Nov 23Nov 27Dec 2Dec 12
28°FNov 16Nov 24Nov 30Dec 3Dec 8Dec 16Dec 24Jan 1Jan 7
24°FDec 3Dec 12Dec 20Dec 26Jan 1Jan 4Jan 9Jan 15Jan 24
20°FDec 15Dec 26Jan 1Jan 5Jan 9Jan 15Jan 20Jan 27Feb 4
16°FDec 31Jan 3Jan 7Jan 12Jan 15Jan 17Jan 21Jan 27Jan 31

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°F248240235230225219215209200
32°F281271264257252247242235224
28°F323311301294289281274265254
24°F363347338331324316307300288
20°F365365365365355347338331319
16°F365365365365365365365364345

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
93% of years
20°F or colder
59% of years
16°F or colder
22% 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
2,467
Cooling degree days, base 65°F
2,151
Growing degree days, base 40°F
8,885
Growing degree days, base 45°F
7,211
Growing degree days, base 50°F
5,692
Growing degree days, base 55°F
4,340
Growing degree days, base 60°F
3,159

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January601159
February463376
March31218214
April11871408
May23218661
June1403852
July0525990
August0484949
September6313757
October93101475
November32414180
December526172

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 14.9 km from Columbia 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 USC00381726 (Clarks Hill 1 W). Public domain.