Joppatowne climate

Joppatowne Frost Dates and Growing Season

NOAA 1991-2020 normals for Aberdeen Phillips Fld, 17.4 km from Joppatowne, elevation 57 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Aberdeen Phillips Fld. 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 10 and the first fall freeze around October 30, a growing season of about 201 days.

Median at 36°F
last April 27, first October 19
Median at 32°F
last April 10, first October 30
Median at 28°F
last March 29, first November 10

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 12May 7May 3Apr 30Apr 27Apr 22Apr 19Apr 15Apr 9
32°FApr 30Apr 22Apr 17Apr 14Apr 10Apr 6Apr 3Mar 31Mar 27
28°FApr 12Apr 6Apr 3Mar 31Mar 29Mar 26Mar 23Mar 19Mar 13
24°FMar 31Mar 28Mar 24Mar 20Mar 18Mar 14Mar 10Mar 6Feb 28
20°FMar 23Mar 18Mar 14Mar 10Mar 7Mar 3Feb 27Feb 22Feb 14
16°FMar 15Mar 9Mar 3Feb 27Feb 23Feb 17Feb 10Feb 5Jan 31

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 5Oct 11Oct 13Oct 16Oct 19Oct 21Oct 24Oct 28Nov 1
32°FOct 14Oct 20Oct 23Oct 27Oct 30Nov 1Nov 3Nov 6Nov 12
28°FOct 28Nov 1Nov 4Nov 7Nov 10Nov 13Nov 16Nov 20Nov 27
24°FNov 6Nov 12Nov 15Nov 19Nov 24Nov 28Dec 1Dec 5Dec 13
20°FNov 18Nov 25Dec 1Dec 3Dec 8Dec 12Dec 17Dec 25Jan 2
16°FDec 4Dec 11Dec 17Dec 23Dec 29Jan 2Jan 7Jan 13Jan 21

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°F197189184180175171166161154
32°F221215211206201198193187178
28°F247241235230226222218213206
24°F276267260256251247242236229
20°F305295289284279274268261254
16°F333324316309304299293286278

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
99% 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
4,706
Cooling degree days, base 65°F
1,171
Growing degree days, base 40°F
6,256
Growing degree days, base 45°F
4,932
Growing degree days, base 50°F
3,767
Growing degree days, base 55°F
2,755
Growing degree days, base 60°F
1,890

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January97905
February82307
March689137
April34414174
May13167404
June14231667
July0373838
August1314778
September43148555
October27922234
November566155
December837011

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 17.4 km from Joppatowne. 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 USW00013701 (Aberdeen Phillips Fld). Public domain.