Jellico climate

Jellico Frost Dates and Growing Season

NOAA 1991-2020 normals for Newcomb, 5.7 km from Jellico, elevation 1014 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Newcomb. 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 18 and the first fall freeze around October 24, a growing season of about 187 days.

Median at 36°F
last April 30, first October 15
Median at 32°F
last April 18, first October 24
Median at 28°F
last April 3, first November 1

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 13May 8May 4May 1Apr 30Apr 26Apr 23Apr 20Apr 16
32°FMay 3Apr 29Apr 25Apr 21Apr 18Apr 15Apr 12Apr 8Apr 3
28°FApr 20Apr 14Apr 10Apr 6Apr 3Mar 31Mar 28Mar 24Mar 18
24°FApr 5Apr 1Mar 29Mar 25Mar 21Mar 17Mar 14Mar 7Feb 28
20°FMar 27Mar 21Mar 16Mar 11Mar 7Mar 2Feb 27Feb 20Feb 9
16°FMar 17Mar 8Mar 2Feb 26Feb 20Feb 14Feb 8Feb 3Jan 26

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 4Oct 7Oct 10Oct 12Oct 15Oct 17Oct 20Oct 23Oct 26
32°FOct 11Oct 15Oct 18Oct 21Oct 24Oct 26Oct 28Oct 31Nov 4
28°FOct 19Oct 25Oct 28Oct 31Nov 1Nov 4Nov 7Nov 11Nov 16
24°FNov 1Nov 3Nov 6Nov 9Nov 12Nov 15Nov 19Nov 25Dec 1
20°FNov 7Nov 14Nov 18Nov 22Nov 27Dec 1Dec 4Dec 9Dec 19
16°FNov 18Nov 26Dec 1Dec 6Dec 12Dec 19Dec 25Dec 31Jan 7

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°F186181176172168165161157150
32°F207200195191187183179174169
28°F233225220215211207203198191
24°F263253246240236230226219213
20°F297283276270263258252245236
16°F330319311303296291283274262

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
100% 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
4,334
Cooling degree days, base 65°F
1,074
Growing degree days, base 40°F
6,446
Growing degree days, base 45°F
5,057
Growing degree days, base 50°F
3,831
Growing degree days, base 55°F
2,766
Growing degree days, base 60°F
1,845

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January913013
February726121
March578274
April30115216
May9882454
June8212654
July0320784
August1286750
September41138548
October27819242
November582054
December808022

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 5.7 km from Jellico. 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 USC00406493 (Newcomb). Public domain.