Gardner climate

Gardner Frost Dates and Growing Season

NOAA 1991-2020 normals for Ashburnham, 8.2 km from Gardner, elevation 1108 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Ashburnham. 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 2 and the first fall freeze around October 13, a growing season of about 163 days.

Median at 36°F
last May 14, first October 2
Median at 32°F
last May 2, first October 13
Median at 28°F
last April 18, first October 25

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

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 2Oct 5Oct 7Oct 11Oct 15
32°FOct 1Oct 4Oct 7Oct 10Oct 13Oct 16Oct 19Oct 24Oct 30
28°FOct 9Oct 14Oct 18Oct 22Oct 25Oct 29Nov 1Nov 5Nov 10
24°FOct 21Oct 27Nov 1Nov 4Nov 8Nov 11Nov 14Nov 19Nov 24
20°FNov 5Nov 11Nov 14Nov 18Nov 21Nov 24Nov 27Dec 1Dec 5
16°FNov 18Nov 22Nov 26Nov 29Dec 1Dec 4Dec 6Dec 11Dec 16

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°F159153149146142138134129123
32°F184177171167163159155151145
28°F209202198193189185181175169
24°F233228222217213210206201194
20°F255249245241236232228223215
16°F274268264258255251247242236

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
7,230
Cooling degree days, base 65°F
394
Growing degree days, base 40°F
4,174
Growing degree days, base 45°F
3,143
Growing degree days, base 50°F
2,244
Growing degree days, base 55°F
1,480
Growing degree days, base 60°F
853

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,33000
February1,14800
March1,02307
April629243
May31712196
June9266427
July16159607
August29114550
September16840327
October519173
November804013
December1,15601

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 8.2 km from Gardner. 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 USC00190190 (Ashburnham). Public domain.