Sebec climate

Sebec Frost Dates and Growing Season

NOAA 1991-2020 normals for Barnard, 3 km from Sebec, elevation 545 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Barnard. 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 12 and the first fall freeze around October 1, a growing season of about 141 days.

Median at 36°F
last May 25, first September 20
Median at 32°F
last May 12, first October 1
Median at 28°F
last April 30, first October 12

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

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 7Sep 12Sep 15Sep 18Sep 20Sep 22Sep 25Sep 29Oct 3
32°FSep 18Sep 23Sep 25Sep 28Oct 1Oct 3Oct 5Oct 9Oct 14
28°FSep 28Oct 2Oct 6Oct 9Oct 12Oct 15Oct 19Oct 24Oct 29
24°FOct 9Oct 16Oct 20Oct 24Oct 27Oct 31Nov 2Nov 6Nov 11
20°FOct 24Oct 31Nov 2Nov 5Nov 7Nov 10Nov 14Nov 18Nov 23
16°FNov 5Nov 9Nov 13Nov 16Nov 20Nov 22Nov 25Nov 28Dec 1

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°F13512912512011611310910599
32°F157152148144141137133128121
28°F185178172169164160156151145
24°F209203199195192188183177169
20°F232226221217214210207202195
16°F250243239235232228225220214

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
8,434
Cooling degree days, base 65°F
240
Growing degree days, base 40°F
3,560
Growing degree days, base 45°F
2,620
Growing degree days, base 50°F
1,810
Growing degree days, base 55°F
1,129
Growing degree days, base 60°F
597

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,54800
February1,32300
March1,16100
April741015
May3916138
June14338348
July3999525
August5779487
September23718247
October593046
November90604
December1,29600

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 3 km from Sebec. 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 USC00170398 (Barnard). Public domain.