Nolan County climate

Nolan County Frost Dates and Growing Season

NOAA 1991-2020 normals for Roscoe, 19.6 km from Nolan County, elevation 2380 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Roscoe. 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 30 and the first fall freeze around November 8, a growing season of about 223 days.

Median at 36°F
last April 8, first October 30
Median at 32°F
last March 30, first November 8
Median at 28°F
last March 16, first November 18

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 27Apr 20Apr 16Apr 12Apr 8Apr 5Apr 3Mar 30Mar 22
32°FApr 17Apr 9Apr 4Apr 2Mar 30Mar 26Mar 21Mar 15Mar 8
28°FApr 4Mar 30Mar 25Mar 20Mar 16Mar 13Mar 8Mar 3Feb 25
24°FMar 25Mar 17Mar 12Mar 8Mar 4Feb 28Feb 24Feb 18Feb 8
20°FMar 12Mar 5Mar 1Feb 24Feb 18Feb 12Feb 5Jan 29Jan 17
16°FMar 4Feb 23Feb 14Feb 7Feb 1Jan 27Jan 19Jan 10Dec 30

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 17Oct 21Oct 24Oct 27Oct 30Nov 1Nov 4Nov 7Nov 12
32°FOct 26Nov 1Nov 3Nov 6Nov 8Nov 11Nov 15Nov 19Nov 25
28°FNov 1Nov 7Nov 11Nov 15Nov 18Nov 22Nov 26Dec 1Dec 4
24°FNov 10Nov 16Nov 21Nov 25Nov 29Dec 2Dec 5Dec 11Dec 20
20°FNov 20Nov 27Dec 2Dec 6Dec 12Dec 19Dec 28Jan 4Jan 15
16°FNov 30Dec 9Dec 16Dec 24Jan 1Jan 7Jan 14Jan 23Feb 4

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°F224217211207203198194189182
32°F249238233228223218213208201
28°F272263256251245240234228218
24°F301290281275270264258251244
20°F334322312305297291284276264
16°F365355346337331323314305293

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
87% 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
2,772
Cooling degree days, base 65°F
2,291
Growing degree days, base 40°F
8,864
Growing degree days, base 45°F
7,263
Growing degree days, base 50°F
5,789
Growing degree days, base 55°F
4,467
Growing degree days, base 60°F
3,300

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January677040
February498381
March32519225
April12286425
May28256693
June1437886
July05571,021
August0527992
September12297735
October114100462
November3729172
December623055

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 19.6 km from Nolan County. Low ground, valleys and open fields freeze earlier and later than a town center or a hillside.

More

Sources

NOAA NCEI U.S. Climate Normals, 1991-2020, annual and seasonal normals for station USC00417743 (Roscoe). Public domain.