Newton climate

Newton Frost Dates and Growing Season

NOAA 1991-2020 normals for Andover Aeroflex AP, 5.6 km from Newton, elevation 583 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Andover Aeroflex AP. 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 19, a growing season of about 175 days.

Median at 36°F
last May 7, first October 6
Median at 32°F
last April 25, first October 19
Median at 28°F
last April 11, first October 31

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

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 9Oct 12Oct 16Oct 22
32°FOct 5Oct 9Oct 13Oct 16Oct 19Oct 22Oct 25Oct 30Nov 3
28°FOct 15Oct 20Oct 25Oct 28Oct 31Nov 2Nov 5Nov 9Nov 13
24°FOct 27Nov 1Nov 5Nov 9Nov 12Nov 15Nov 18Nov 22Nov 29
20°FNov 10Nov 14Nov 19Nov 22Nov 26Nov 29Dec 2Dec 6Dec 13
16°FNov 21Nov 27Dec 1Dec 4Dec 7Dec 11Dec 16Dec 21Dec 27

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°F172166161157152148144138132
32°F198189184179175170166161153
28°F222215211206202198193187178
24°F248240235231227223219213207
20°F273266260256252248243237230
16°F297288283278274270265260252

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
5,927
Cooling degree days, base 65°F
669
Growing degree days, base 40°F
5,080
Growing degree days, base 45°F
3,904
Growing degree days, base 50°F
2,877
Growing degree days, base 55°F
1,992
Growing degree days, base 60°F
1,252

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,16500
February99701
March842015
April470597
May20534303
June38130543
July4243704
August11191645
September10860404
October4006138
November690023
December99804

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 5.6 km from Newton. 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 USW00054779 (Andover Aeroflex AP). Public domain.