Mount Laurel climate

Mount Laurel Frost Dates and Growing Season

NOAA 1991-2020 normals for Mt Holly S Jersey AP, 4.5 km from Mount Laurel, elevation 53 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Mt Holly S Jersey AP. 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 15 and the first fall freeze around October 28, a growing season of about 195 days.

Median at 36°F
last April 28, first October 16
Median at 32°F
last April 15, first October 28
Median at 28°F
last April 1, first November 8

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 15May 8May 4May 1Apr 28Apr 25Apr 22Apr 19Apr 13
32°FMay 2Apr 25Apr 21Apr 18Apr 15Apr 12Apr 8Apr 4Mar 31
28°FApr 15Apr 10Apr 7Apr 4Apr 1Mar 30Mar 26Mar 22Mar 16
24°FApr 2Mar 29Mar 25Mar 22Mar 19Mar 16Mar 13Mar 9Mar 3
20°FMar 21Mar 17Mar 13Mar 9Mar 6Mar 3Feb 28Feb 24Feb 15
16°FMar 13Mar 6Mar 2Feb 27Feb 22Feb 18Feb 13Feb 8Feb 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 4Oct 7Oct 10Oct 13Oct 16Oct 19Oct 22Oct 26Oct 30
32°FOct 12Oct 17Oct 21Oct 25Oct 28Oct 31Nov 2Nov 5Nov 9
28°FOct 25Nov 1Nov 3Nov 5Nov 8Nov 11Nov 14Nov 17Nov 22
24°FNov 5Nov 10Nov 13Nov 17Nov 20Nov 24Nov 28Dec 2Dec 8
20°FNov 17Nov 24Nov 28Dec 1Dec 5Dec 9Dec 14Dec 19Dec 26
16°FDec 1Dec 7Dec 13Dec 17Dec 22Dec 27Jan 1Jan 6Jan 15

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°F190184178174170166161156148
32°F215208203198195191186180173
28°F243235230226222217213209201
24°F271263257252248243239234227
20°F300291284280276271265258249
16°F327317311306301296290283274

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
4,880
Cooling degree days, base 65°F
1,074
Growing degree days, base 40°F
6,045
Growing degree days, base 45°F
4,739
Growing degree days, base 50°F
3,591
Growing degree days, base 55°F
2,604
Growing degree days, base 60°F
1,764

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January99806
February84407
March700135
April38613142
May14760381
June18211644
July0360825
August2294756
September53119516
October29817216
November578051
December857014

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 4.5 km from Mount Laurel. 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 USW00093780 (Mt Holly S Jersey AP). Public domain.