Thomas County climate

Thomas County Frost Dates and Growing Season

NOAA 1991-2020 normals for Mullen, 42.9 km from Thomas County, elevation 3215 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Mullen. 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 May 7 and the first fall freeze around October 5, a growing season of about 150 days.

Median at 36°F
last May 16, first September 27
Median at 32°F
last May 7, first October 5
Median at 28°F
last April 28, first October 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°FMay 29May 26May 22May 19May 16May 14May 11May 8May 4
32°FMay 22May 17May 12May 9May 7May 4May 2Apr 30Apr 24
28°FMay 10May 5May 2Apr 30Apr 28Apr 25Apr 22Apr 17Apr 13
24°FMay 1Apr 27Apr 24Apr 20Apr 17Apr 13Apr 10Apr 6Apr 1
20°FApr 22Apr 17Apr 13Apr 9Apr 6Apr 2Mar 30Mar 25Mar 19
16°FApr 15Apr 8Apr 3Mar 31Mar 27Mar 22Mar 18Mar 13Mar 8

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 13Sep 18Sep 21Sep 24Sep 27Sep 30Oct 2Oct 5Oct 9
32°FSep 22Sep 27Oct 1Oct 3Oct 5Oct 8Oct 11Oct 13Oct 17
28°FSep 30Oct 5Oct 9Oct 12Oct 14Oct 17Oct 20Oct 23Oct 27
24°FOct 9Oct 15Oct 18Oct 21Oct 24Oct 26Oct 28Nov 1Nov 5
20°FOct 18Oct 23Oct 26Oct 29Nov 1Nov 3Nov 7Nov 10Nov 16
16°FOct 24Oct 30Nov 2Nov 5Nov 8Nov 11Nov 15Nov 19Nov 25

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°F150144140136132128124120113
32°F167162157154150146143137130
28°F189182177173169165161157149
24°F209202196192188184181175169
20°F231224218213208204199193186
16°F250244237232227222217210201

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
6,695
Cooling degree days, base 65°F
710
Growing degree days, base 40°F
4,838
Growing degree days, base 45°F
3,739
Growing degree days, base 50°F
2,783
Growing degree days, base 55°F
1,959
Growing degree days, base 60°F
1,265

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,21400
February1,03304
March851021
April563272
May28829257
June52124523
July7264722
August21214659
September14273393
October5034116
November846017
December1,17601

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 42.9 km from Thomas 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 USC00255700 (Mullen). Public domain.