Ector County climate

Ector County Frost Dates and Growing Season

NOAA 1991-2020 normals for Penwell, 15.5 km from Ector County, elevation 2933 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Penwell. 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 14 and the first fall freeze around November 14, a growing season of about 244 days.

Median at 36°F
last March 31, first November 5
Median at 32°F
last March 14, first November 14
Median at 28°F
last March 2, first November 25

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 19Apr 11Apr 6Apr 3Mar 31Mar 27Mar 21Mar 15Mar 9
32°FApr 6Mar 31Mar 24Mar 18Mar 14Mar 10Mar 6Mar 1Feb 23
28°FMar 24Mar 16Mar 10Mar 6Mar 2Feb 26Feb 21Feb 15Feb 7
24°FMar 12Mar 2Feb 25Feb 19Feb 13Feb 6Feb 1Jan 24Jan 15
20°FMar 1Feb 19Feb 9Feb 2Jan 27Jan 19Jan 11Jan 1Dec 16
16°FFeb 15Feb 3Jan 27Jan 17Jan 10Jan 2Dec 27Dec 17Dec 9

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 21Oct 27Oct 30Nov 2Nov 5Nov 8Nov 11Nov 14Nov 20
32°FOct 30Nov 4Nov 8Nov 11Nov 14Nov 17Nov 22Nov 26Dec 2
28°FNov 8Nov 13Nov 17Nov 21Nov 25Nov 29Dec 2Dec 6Dec 13
24°FNov 16Nov 23Nov 28Dec 2Dec 6Dec 10Dec 17Dec 25Jan 3
20°FNov 29Dec 4Dec 11Dec 17Dec 23Dec 29Jan 3Jan 13Jan 27
16°FDec 4Dec 11Dec 18Dec 23Dec 30Jan 5Jan 13Jan 25Feb 5

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°F244236230224220215210203194
32°F270262254250244240234227216
28°F299287279275269262257250241
24°F334322312305297290282274262
20°F365357349341334326318308294
16°F365365365365365359350340327

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
99% of years
20°F or colder
87% of years
16°F or colder
47% 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
2,261
Cooling degree days, base 65°F
2,786
Growing degree days, base 40°F
9,746
Growing degree days, base 45°F
8,064
Growing degree days, base 50°F
6,507
Growing degree days, base 55°F
5,112
Growing degree days, base 60°F
3,872

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January590049
February4093103
March23533294
April76125505
May12338791
June05551,005
July06081,073
August06011,066
September6367812
October66140543
November30815208
December560060

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 15.5 km from Ector 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 USC00416932 (Penwell). Public domain.