Spring City climate

Spring City Frost Dates and Growing Season

NOAA 1991-2020 normals for Spring City, 1.8 km from Spring City, elevation 755 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Spring City. 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 11 and the first fall freeze around October 29, a growing season of about 200 days.

Median at 36°F
last April 24, first October 20
Median at 32°F
last April 11, first October 29
Median at 28°F
last March 30, first November 7

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

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 8Oct 12Oct 15Oct 18Oct 20Oct 22Oct 25Oct 28Nov 1
32°FOct 16Oct 21Oct 24Oct 26Oct 29Nov 1Nov 2Nov 6Nov 11
28°FOct 26Oct 31Nov 2Nov 5Nov 7Nov 10Nov 14Nov 18Nov 26
24°FNov 5Nov 9Nov 13Nov 16Nov 20Nov 23Nov 28Dec 2Dec 7
20°FNov 14Nov 21Nov 25Nov 30Dec 3Dec 8Dec 14Dec 23Dec 29
16°FNov 28Dec 4Dec 11Dec 20Dec 26Dec 31Jan 2Jan 8Jan 16

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°F198192187183178174170165159
32°F220212208204200196191185178
28°F249241234229224219214209201
24°F276267261256251246239233224
20°F311299291284278272266259250
16°F342333325319311305298290276

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
4,019
Cooling degree days, base 65°F
1,246
Growing degree days, base 40°F
6,794
Growing degree days, base 45°F
5,357
Growing degree days, base 50°F
4,092
Growing degree days, base 55°F
2,995
Growing degree days, base 60°F
2,050

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January873012
February688018
March535280
April25517242
May8191477
June3244691
July0363828
August0340804
September26167591
October23422274
November547154
December778020

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 1.8 km from Spring City. 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 USC00408540 (Spring City). Public domain.