Carrollton climate

Carrollton Frost Dates and Growing Season

NOAA 1991-2020 normals for Dennison Wtr Wks, 28.7 km from Carrollton, elevation 860 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Dennison Wtr Wks. 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 29 and the first fall freeze around October 15, a growing season of about 170 days.

Median at 36°F
last May 10, first October 5
Median at 32°F
last April 29, first October 15
Median at 28°F
last April 17, first October 28

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 27May 21May 17May 13May 10May 7May 3Apr 30Apr 25
32°FMay 17May 10May 5May 1Apr 29Apr 26Apr 24Apr 21Apr 17
28°FMay 1Apr 27Apr 22Apr 19Apr 17Apr 14Apr 11Apr 7Apr 2
24°FApr 17Apr 13Apr 9Apr 6Apr 4Apr 2Mar 30Mar 26Mar 19
20°FApr 7Apr 2Mar 31Mar 28Mar 24Mar 20Mar 17Mar 12Mar 7
16°FMar 29Mar 24Mar 19Mar 15Mar 11Mar 8Mar 4Feb 28Feb 22

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°FSep 22Sep 27Oct 1Oct 2Oct 5Oct 7Oct 10Oct 13Oct 19
32°FOct 2Oct 6Oct 9Oct 12Oct 15Oct 18Oct 21Oct 25Oct 30
28°FOct 11Oct 17Oct 21Oct 25Oct 28Oct 31Nov 2Nov 5Nov 11
24°FOct 23Oct 29Nov 1Nov 4Nov 7Nov 10Nov 14Nov 20Nov 28
20°FNov 2Nov 8Nov 12Nov 17Nov 21Nov 26Nov 30Dec 4Dec 9
16°FNov 13Nov 20Nov 26Dec 1Dec 4Dec 8Dec 14Dec 20Dec 27

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°F168161156151147143138133126
32°F190184178174170165161155147
28°F213207202198194190185180171
24°F239231225221217213209204197
20°F266257251246240235230225218
16°F295285278272266261255248240

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
5,820
Cooling degree days, base 65°F
776
Growing degree days, base 40°F
5,322
Growing degree days, base 45°F
4,126
Growing degree days, base 50°F
3,075
Growing degree days, base 55°F
2,169
Growing degree days, base 60°F
1,400

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,15803
February96605
March808132
April4527119
May18956346
June36158574
July4255716
August12209662
September10581429
October39811151
November696032
December99705

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 28.7 km from Carrollton. 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 USC00332160 (Dennison Wtr Wks). Public domain.