Johnsonville climate

Johnsonville Frost Dates and Growing Season

NOAA 1991-2020 normals for Camden, 11.7 km from Johnsonville, elevation 423 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Camden. 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 April 3 and the first fall freeze around November 1, a growing season of about 214 days.

Median at 36°F
last April 15, first October 23
Median at 32°F
last April 3, first November 1
Median at 28°F
last March 20, first November 14

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

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 10Oct 15Oct 18Oct 21Oct 23Oct 25Oct 28Oct 31Nov 4
32°FOct 19Oct 24Oct 27Oct 30Nov 1Nov 3Nov 7Nov 10Nov 16
28°FNov 1Nov 4Nov 7Nov 10Nov 14Nov 16Nov 20Nov 25Dec 1
24°FNov 8Nov 14Nov 17Nov 20Nov 25Nov 30Dec 2Dec 7Dec 17
20°FNov 19Nov 27Dec 1Dec 5Dec 9Dec 16Dec 22Dec 29Jan 6
16°FDec 3Dec 12Dec 21Dec 28Jan 1Jan 4Jan 9Jan 14Jan 22

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°F212204199195191188184178170
32°F235227222218214210205200193
28°F264255249243239234229224216
24°F291281275269264258254246238
20°F322311303296291285279271261
16°F348337332325320313306298287

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
100% of years
16°F or colder
97% 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
3,526
Cooling degree days, base 65°F
1,732
Growing degree days, base 40°F
7,706
Growing degree days, base 45°F
6,210
Growing degree days, base 50°F
4,857
Growing degree days, base 55°F
3,663
Growing degree days, base 60°F
2,622

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January823026
February622145
March44910138
April19850322
May50157572
June2339787
July0459924
August0428893
September20230660
October18653346
November4634105
December712140

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 11.7 km from Johnsonville. 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 USC00401352 (Camden). Public domain.