Plainfield climate

Plainfield Frost Dates and Growing Season

NOAA 1991-2020 normals for Hampton, 15.3 km from Plainfield, elevation 490 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Hampton. 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 30 and the first fall freeze around October 15, a growing season of about 167 days.

Median at 36°F
last May 10, first October 3
Median at 32°F
last April 30, first October 15
Median at 28°F
last April 16, 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 15May 12May 10May 8May 5May 3Apr 29
32°FMay 11May 7May 4May 2Apr 30Apr 27Apr 24Apr 21Apr 18
28°FApr 30Apr 25Apr 21Apr 19Apr 16Apr 13Apr 11Apr 8Apr 4
24°FApr 17Apr 11Apr 8Apr 5Apr 3Apr 1Mar 31Mar 27Mar 20
20°FApr 5Apr 1Mar 31Mar 27Mar 24Mar 20Mar 17Mar 14Mar 9
16°FMar 29Mar 24Mar 20Mar 17Mar 15Mar 12Mar 9Mar 6Feb 28

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 22Sep 26Sep 29Oct 1Oct 3Oct 5Oct 8Oct 11Oct 16
32°FOct 1Oct 5Oct 9Oct 12Oct 15Oct 18Oct 21Oct 25Oct 29
28°FOct 13Oct 17Oct 21Oct 25Oct 28Oct 30Nov 1Nov 4Nov 9
24°FOct 25Oct 30Nov 2Nov 5Nov 7Nov 10Nov 14Nov 18Nov 24
20°FNov 6Nov 10Nov 14Nov 17Nov 20Nov 25Nov 28Dec 1Dec 8
16°FNov 17Nov 22Nov 27Dec 1Dec 2Dec 5Dec 9Dec 14Dec 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°F162157153150146143138134128
32°F187180175171167164159155149
28°F210205200197193189185181174
24°F238231226221217213209205198
20°F263255249245240237232226219
16°F286278272267262258253248240

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
6,396
Cooling degree days, base 65°F
436
Growing degree days, base 40°F
4,513
Growing degree days, base 45°F
3,389
Growing degree days, base 50°F
2,427
Growing degree days, base 55°F
1,606
Growing degree days, base 60°F
936

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,18400
February1,03201
March91009
April569252
May28012220
June7471448
July11172626
August22129572
September13847360
October4373115
November717022
December1,02102

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 15.3 km from Plainfield. 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 USC00063420 (Hampton). Public domain.