Howard County climate

Howard County Frost Dates and Growing Season

NOAA 1991-2020 normals for Big Spring, 7.1 km from Howard County, elevation 2510 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Big Spring. 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 20 and the first fall freeze around November 13, a growing season of about 239 days.

Median at 36°F
last April 3, first November 5
Median at 32°F
last March 20, first November 13
Median at 28°F
last March 6, first November 24

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 24Apr 18Apr 11Apr 7Apr 3Mar 31Mar 28Mar 23Mar 15
32°FApr 7Apr 2Mar 30Mar 24Mar 20Mar 15Mar 11Mar 7Mar 1
28°FMar 29Mar 21Mar 14Mar 9Mar 6Mar 2Feb 28Feb 23Feb 16
24°FMar 13Mar 6Mar 2Feb 28Feb 23Feb 18Feb 13Feb 4Jan 24
20°FMar 3Feb 24Feb 18Feb 11Feb 4Jan 31Jan 21Jan 12Dec 31
16°FFeb 18Feb 8Feb 2Jan 27Jan 19Jan 12Jan 5Dec 29Dec 17

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 23Oct 29Nov 1Nov 3Nov 5Nov 8Nov 10Nov 13Nov 17
32°FOct 31Nov 4Nov 7Nov 10Nov 13Nov 16Nov 19Nov 23Nov 29
28°FNov 7Nov 13Nov 16Nov 20Nov 24Nov 27Dec 1Dec 5Dec 12
24°FNov 18Nov 24Nov 29Dec 3Dec 8Dec 12Dec 18Dec 25Jan 2
20°FNov 30Dec 8Dec 14Dec 20Dec 27Jan 1Jan 7Jan 16Jan 29
16°FDec 9Dec 16Dec 23Dec 30Jan 4Jan 12Jan 19Jan 29Feb 6

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°F239230224219214209205199191
32°F261253248243239233227221212
28°F287277271266261256252245235
24°F323310303296290284276269259
20°F363348338330322315307299286
16°F365365365365357348339330315

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
92% of years
16°F or colder
58% 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
2,558
Cooling degree days, base 65°F
2,508
Growing degree days, base 40°F
9,230
Growing degree days, base 45°F
7,596
Growing degree days, base 50°F
6,091
Growing degree days, base 55°F
4,736
Growing degree days, base 60°F
3,542

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January629047
February462390
March28528255
April10799451
May22278721
June1481930
July05871,052
August05611,026
September11333773
October93126507
November34512186
December605054

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 7.1 km from Howard 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 USW00023041 (Big Spring). Public domain.