South Hooksett climate

South Hooksett Frost Dates and Growing Season

NOAA 1991-2020 normals for Massabesic Lake, 5.4 km from South Hooksett, elevation 253 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Massabesic Lake. 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 11, a growing season of about 164 days.

Median at 36°F
last May 12, first October 2
Median at 32°F
last April 30, first October 11
Median at 28°F
last April 17, first October 24

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 24May 20May 17May 15May 12May 9May 6May 3Apr 30
32°FMay 14May 8May 4May 2Apr 30Apr 28Apr 25Apr 22Apr 19
28°FMay 2Apr 27Apr 23Apr 20Apr 17Apr 14Apr 11Apr 9Apr 6
24°FApr 18Apr 13Apr 10Apr 7Apr 5Apr 3Apr 1Mar 30Mar 25
20°FApr 7Apr 4Apr 1Mar 31Mar 28Mar 25Mar 21Mar 18Mar 13
16°FApr 1Mar 29Mar 26Mar 22Mar 19Mar 16Mar 14Mar 10Mar 6

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 20Sep 25Sep 27Sep 30Oct 2Oct 4Oct 6Oct 9Oct 14
32°FSep 30Oct 3Oct 6Oct 8Oct 11Oct 14Oct 17Oct 22Oct 27
28°FOct 8Oct 13Oct 17Oct 20Oct 24Oct 28Oct 31Nov 3Nov 8
24°FOct 20Oct 26Oct 30Nov 2Nov 5Nov 8Nov 11Nov 15Nov 22
20°FNov 3Nov 9Nov 12Nov 16Nov 19Nov 22Nov 26Nov 29Dec 3
16°FNov 18Nov 22Nov 26Nov 29Dec 1Dec 3Dec 6Dec 10Dec 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°F160154149145141139135131125
32°F183176171167164160156152146
28°F209202197193188184180175168
24°F233226221217213210206200192
20°F257250244240236231227223216
16°F276269264260256251248244237

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
6,907
Cooling degree days, base 65°F
538
Growing degree days, base 40°F
4,490
Growing degree days, base 45°F
3,425
Growing degree days, base 50°F
2,496
Growing degree days, base 55°F
1,700
Growing degree days, base 60°F
1,045

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,32200
February1,12300
March98507
April587254
May28218226
June7296475
July15201651
August21159603
September13958375
October480392
November770013
December1,11100

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 5.4 km from South Hooksett. 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 USC00275211 (Massabesic Lake). Public domain.