Elverson climate

Elverson Frost Dates and Growing Season

NOAA 1991-2020 normals for Glenmoore, 9.7 km from Elverson, elevation 500 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Glenmoore. 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 April 11 and the first fall freeze around November 1, a growing season of about 205 days.

Median at 36°F
last April 26, first October 19
Median at 32°F
last April 11, first November 1
Median at 28°F
last March 31, first November 15

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 11May 5May 1Apr 30Apr 26Apr 22Apr 20Apr 16Apr 12
32°FApr 29Apr 21Apr 17Apr 14Apr 11Apr 8Apr 5Apr 1Mar 28
28°FApr 11Apr 6Apr 4Apr 1Mar 31Mar 27Mar 24Mar 20Mar 15
24°FMar 31Mar 27Mar 24Mar 21Mar 19Mar 16Mar 12Mar 8Mar 2
20°FMar 22Mar 18Mar 15Mar 12Mar 8Mar 6Mar 2Feb 27Feb 21
16°FMar 15Mar 10Mar 6Mar 3Feb 28Feb 24Feb 19Feb 12Feb 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 6Oct 10Oct 13Oct 16Oct 19Oct 23Oct 26Oct 30Nov 3
32°FOct 16Oct 22Oct 27Oct 30Nov 1Nov 4Nov 7Nov 11Nov 17
28°FOct 31Nov 5Nov 9Nov 12Nov 15Nov 19Nov 22Nov 27Dec 3
24°FNov 12Nov 18Nov 22Nov 26Dec 1Dec 2Dec 6Dec 12Dec 20
20°FNov 23Dec 1Dec 4Dec 8Dec 14Dec 19Dec 24Dec 28Jan 5
16°FDec 7Dec 14Dec 21Dec 26Dec 30Jan 2Jan 7Jan 14Jan 22

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°F198192186182177173169164156
32°F225217212208205200196190182
28°F253244240235232227222217210
24°F280272266261256250246240233
20°F304296290286280275270264255
16°F328319311306302298293287279

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
5,377
Cooling degree days, base 65°F
859
Growing degree days, base 40°F
5,562
Growing degree days, base 45°F
4,327
Growing degree days, base 50°F
3,245
Growing degree days, base 55°F
2,306
Growing degree days, base 60°F
1,510

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,07702
February92005
March784027
April4299121
May16743348
June22164593
July1293756
August4238699
September77101474
October34612177
November633037
December91807

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 9.7 km from Elverson. 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 USC00363321 (Glenmoore). Public domain.