Hamilton Square climate

Hamilton Square Frost Dates and Growing Season

NOAA 1991-2020 normals for Hightstown 2 W, 8.7 km from Hamilton Square, elevation 100 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Hightstown 2 W. 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 25 and the first fall freeze around October 16, a growing season of about 173 days.

Median at 36°F
last May 8, first October 6
Median at 32°F
last April 25, first October 16
Median at 28°F
last April 10, first October 28

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 23May 18May 14May 11May 8May 5May 2Apr 29Apr 24
32°FMay 12May 6May 2Apr 29Apr 25Apr 22Apr 19Apr 16Apr 12
28°FApr 26Apr 21Apr 17Apr 14Apr 10Apr 7Apr 4Mar 31Mar 26
24°FApr 10Apr 5Apr 2Mar 30Mar 28Mar 24Mar 20Mar 17Mar 11
20°FMar 30Mar 26Mar 21Mar 18Mar 15Mar 12Mar 9Mar 5Feb 27
16°FMar 20Mar 15Mar 11Mar 8Mar 5Mar 1Feb 27Feb 21Feb 12

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°FSep 26Sep 30Oct 2Oct 4Oct 6Oct 8Oct 11Oct 15Oct 19
32°FOct 4Oct 7Oct 10Oct 13Oct 16Oct 19Oct 22Oct 25Oct 29
28°FOct 13Oct 18Oct 22Oct 25Oct 28Oct 30Nov 2Nov 5Nov 11
24°FOct 25Oct 30Nov 2Nov 5Nov 8Nov 11Nov 15Nov 20Nov 27
20°FNov 5Nov 11Nov 15Nov 18Nov 22Nov 27Dec 1Dec 6Dec 15
16°FNov 16Nov 23Nov 29Dec 2Dec 7Dec 11Dec 17Dec 23Dec 30

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°F171164160155151147143138132
32°F194187182178173169164159153
28°F221214209204200196191185178
24°F250242235231226222217212204
20°F279269264259253248244238229
16°F304295289283278273268262253

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
5,315
Cooling degree days, base 65°F
903
Growing degree days, base 40°F
5,606
Growing degree days, base 45°F
4,359
Growing degree days, base 50°F
3,272
Growing degree days, base 55°F
2,334
Growing degree days, base 60°F
1,544

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,05503
February90003
March766124
April43110121
May18447335
June33175593
July2307770
August5248708
September72103483
October34412181
November626042
December89709

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 8.7 km from Hamilton Square. 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 USC00283951 (Hightstown 2 W). Public domain.