Amesbury climate

Amesbury Frost Dates and Growing Season

NOAA 1991-2020 normals for Haverhill, 15.3 km from Amesbury, elevation 20 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Haverhill. 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 May 1 and the first fall freeze around October 12, a growing season of about 163 days.

Median at 36°F
last May 12, first October 3
Median at 32°F
last May 1, first October 12
Median at 28°F
last April 19, first October 23

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

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 21Sep 26Sep 29Oct 1Oct 3Oct 5Oct 7Oct 11Oct 15
32°FOct 1Oct 3Oct 6Oct 9Oct 12Oct 15Oct 19Oct 23Oct 28
28°FOct 7Oct 13Oct 17Oct 20Oct 23Oct 26Oct 30Nov 2Nov 7
24°FOct 18Oct 24Oct 29Nov 1Nov 3Nov 6Nov 10Nov 14Nov 20
20°FNov 2Nov 7Nov 11Nov 14Nov 18Nov 22Nov 26Nov 30Dec 5
16°FNov 18Nov 23Nov 27Nov 30Dec 2Dec 5Dec 8Dec 12Dec 20

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°F159153149146142139135131125
32°F183177171167163159155151144
28°F208201195191186183178173168
24°F233225220215211207202197192
20°F258251246241236232228222214
16°F283275270266262257253247240

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
6,561
Cooling degree days, base 65°F
556
Growing degree days, base 40°F
4,574
Growing degree days, base 45°F
3,476
Growing degree days, base 50°F
2,524
Growing degree days, base 55°F
1,723
Growing degree days, base 60°F
1,066

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,22301
February1,05700
March94108
April583249
May29217212
June7990463
July8217674
August17170618
September13655372
October4473106
November734020
December1,04602

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 Amesbury. 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 USC00193505 (Haverhill). Public domain.