Haddon Heights climate

Haddon Heights Frost Dates and Growing Season

NOAA 1991-2020 normals for Phila Franklin Inst, 12.9 km from Haddon Heights, elevation 60 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Phila Franklin Inst. 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 17, a growing season of about 232 days.

Median at 36°F
last April 8, first November 5
Median at 32°F
last March 30, first November 17
Median at 28°F
last March 17, first November 29

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 23Apr 19Apr 15Apr 11Apr 8Apr 6Apr 3Apr 1Mar 27
32°FApr 12Apr 7Apr 4Apr 1Mar 30Mar 27Mar 24Mar 20Mar 15
28°FMar 31Mar 27Mar 23Mar 20Mar 17Mar 15Mar 11Mar 7Mar 1
24°FMar 22Mar 17Mar 14Mar 11Mar 8Mar 5Mar 1Feb 25Feb 18
20°FMar 14Mar 8Mar 5Mar 1Feb 25Feb 20Feb 15Feb 8Feb 2
16°FMar 5Feb 27Feb 21Feb 15Feb 9Feb 4Jan 31Jan 25Jan 16

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

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°F230224218215211207204199192
32°F255248242237232228223219214
28°F282273267262257252247243235
24°F305296290285281275270264255
20°F328319313307303298294287278
16°F354340333329324318312306300

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
95% 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
4,212
Cooling degree days, base 65°F
1,603
Growing degree days, base 40°F
7,063
Growing degree days, base 45°F
5,661
Growing degree days, base 50°F
4,429
Growing degree days, base 55°F
3,344
Growing degree days, base 60°F
2,402

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January93907
February777010
March624356
April29326222
May81112496
June7319762
July0476941
August1414879
September21216645
October20436310
November486185
December780017

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 12.9 km from Haddon Heights. 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 USC00366886 (Phila Franklin Inst). Public domain.