Jack County climate

Jack County Frost Dates and Growing Season

NOAA 1991-2020 normals for Jacksboro, 3.1 km from Jack County, elevation 1081 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Jacksboro. 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 28 and the first fall freeze around November 7, a growing season of about 225 days.

Median at 36°F
last April 11, first October 29
Median at 32°F
last March 28, first November 7
Median at 28°F
last March 14, first November 16

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 28Apr 23Apr 19Apr 15Apr 11Apr 7Apr 3Mar 30Mar 23
32°FApr 18Apr 9Apr 4Apr 1Mar 28Mar 24Mar 19Mar 15Mar 9
28°FApr 3Mar 28Mar 22Mar 17Mar 14Mar 10Mar 6Mar 2Feb 24
24°FMar 23Mar 15Mar 11Mar 6Mar 3Feb 28Feb 24Feb 18Feb 10
20°FMar 11Mar 5Mar 1Feb 23Feb 16Feb 10Feb 2Jan 29Jan 19
16°FMar 2Feb 21Feb 13Feb 5Jan 31Jan 26Jan 19Jan 11Dec 31

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 16Oct 20Oct 23Oct 26Oct 29Nov 1Nov 3Nov 7Nov 12
32°FOct 23Oct 29Nov 1Nov 4Nov 7Nov 10Nov 13Nov 17Nov 23
28°FNov 1Nov 5Nov 9Nov 13Nov 16Nov 20Nov 24Nov 30Dec 4
24°FNov 9Nov 15Nov 20Nov 25Nov 29Dec 2Dec 5Dec 11Dec 18
20°FNov 19Nov 27Dec 2Dec 7Dec 13Dec 17Dec 23Dec 31Jan 8
16°FDec 1Dec 8Dec 15Dec 22Dec 30Jan 4Jan 10Jan 18Feb 1

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°F225217212207203198193188180
32°F250241236230225219214208200
28°F274265258253247243237231221
24°F302290282277271265260254244
20°F336323314307300292285278267
16°F365357345339333326319309300

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
99% of years
16°F or colder
88% 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
2,865
Cooling degree days, base 65°F
2,345
Growing degree days, base 40°F
8,845
Growing degree days, base 45°F
7,261
Growing degree days, base 50°F
5,808
Growing degree days, base 55°F
4,501
Growing degree days, base 60°F
3,345

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January700140
February517380
March33621218
April13971395
May28226664
June1431880
July05771,041
August05671,032
September12326763
October122107461
November37214177
December638157

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 3.1 km from Jack County. 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 USC00414517 (Jacksboro). Public domain.