Thorndale climate

Thorndale Frost Dates and Growing Season

NOAA 1991-2020 normals for Granger Dam, 16 km from Thorndale, elevation 555 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Granger Dam. 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 5 and the first fall freeze around November 22, a growing season of about 261 days.

Median at 36°F
last March 20, first November 11
Median at 32°F
last March 5, first November 22
Median at 28°F
last February 20, first December 6

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 11Apr 4Mar 31Mar 25Mar 20Mar 15Mar 11Mar 5Feb 27
32°FMar 31Mar 20Mar 14Mar 9Mar 5Mar 1Feb 25Feb 20Feb 13
28°FMar 12Mar 6Mar 2Feb 25Feb 20Feb 15Feb 10Feb 2Jan 24
24°FMar 5Feb 25Feb 16Feb 10Feb 3Jan 28Jan 21Jan 11Dec 31
20°FFeb 26Feb 13Feb 4Jan 29Jan 22Jan 16Jan 10Jan 3Dec 22
16°FFeb 13Feb 7Feb 2Jan 28Jan 21Jan 15Jan 10Jan 5Jan 2

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 28Nov 1Nov 5Nov 8Nov 11Nov 15Nov 19Nov 24Dec 1
32°FNov 4Nov 10Nov 14Nov 19Nov 22Nov 26Dec 1Dec 5Dec 11
28°FNov 14Nov 21Nov 26Dec 1Dec 6Dec 11Dec 17Dec 24Jan 2
24°FNov 24Dec 4Dec 11Dec 19Dec 26Jan 1Jan 6Jan 13Jan 31
20°FDec 9Dec 21Jan 1Jan 3Jan 8Jan 13Jan 20Feb 1Feb 13
16°FJan 1Jan 2Jan 7Jan 10Jan 15Jan 22Feb 1Feb 4Feb 10

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°F264255248243238232226219210
32°F291280273266261256251242233
28°F329314306298292286277270259
24°F364349339332324317309301288
20°F365365365365363354345336320
16°F365365365365365365365365355

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
99% of years
24°F or colder
92% of years
20°F or colder
54% of years
16°F or colder
16% 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
1,860
Cooling degree days, base 65°F
2,802
Growing degree days, base 40°F
10,128
Growing degree days, base 45°F
8,408
Growing degree days, base 50°F
6,784
Growing degree days, base 55°F
5,297
Growing degree days, base 60°F
3,967

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January5024101
February34611154
March20244330
April64117505
May7299756
June0480930
July05941,059
August06061,071
September3418865
October53180595
November22740293
December4559126

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 16 km from Thorndale. 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 USC00413686 (Granger Dam). Public domain.