East Pepperell climate

East Pepperell Frost Dates and Growing Season

NOAA 1991-2020 normals for Nashua Cwsu, 10.8 km from East Pepperell, elevation 180 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Nashua Cwsu. 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 29 and the first fall freeze around October 8, a growing season of about 162 days.

Median at 36°F
last May 10, first October 1
Median at 32°F
last April 29, first October 8
Median at 28°F
last April 16, first October 20

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

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 24Sep 27Sep 30Oct 1Oct 3Oct 5Oct 8Oct 12
32°FSep 28Oct 2Oct 4Oct 6Oct 8Oct 12Oct 15Oct 19Oct 25
28°FOct 6Oct 10Oct 13Oct 16Oct 20Oct 24Oct 28Nov 1Nov 5
24°FOct 15Oct 21Oct 26Oct 30Nov 2Nov 4Nov 7Nov 11Nov 16
20°FOct 29Nov 2Nov 6Nov 10Nov 13Nov 16Nov 20Nov 23Nov 29
16°FNov 12Nov 16Nov 20Nov 24Nov 27Nov 30Dec 2Dec 5Dec 11

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°F159154150146143139136132125
32°F180174169165162159155152145
28°F204197193189185181177173166
24°F228222216213209205201196188
20°F252244238234230226222217211
16°F273265260255251247241236228

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
6,593
Cooling degree days, base 65°F
704
Growing degree days, base 40°F
4,819
Growing degree days, base 45°F
3,721
Growing degree days, base 50°F
2,767
Growing degree days, base 55°F
1,956
Growing degree days, base 60°F
1,265

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,26600
February1,07801
March93905
April558465
May25530260
June54123520
July8260717
August11203657
September12181414
October4493111
November756018
December1,09900

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 10.8 km from East Pepperell. 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 USC00275703 (Nashua Cwsu). Public domain.