Babson Park climate

Babson Park Frost Dates and Growing Season

NOAA 1991-2020 normals for Mtn Lake, 14 km from Babson Park, elevation 125 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Mtn Lake. 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 February 4 and the first fall freeze around January 4, a growing season of about 332 days.

Median at 36°F
last February 25, first December 21
Median at 32°F
last February 4, first January 4
Median at 28°F
last January 20, first January 8

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°FMar 20Mar 14Mar 7Mar 2Feb 25Feb 18Feb 10Feb 1Jan 22
32°FMar 11Mar 1Feb 21Feb 13Feb 4Jan 29Jan 22Jan 11Jan 1
28°FFeb 21Feb 9Jan 31Jan 25Jan 20Jan 12Jan 6Dec 31Dec 27
24°FJan 24Jan 21Jan 14Jan 10Jan 6Jan 1Dec 31Dec 27Dec 21
20°F–––––––––
16°F–––––––––

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°FNov 29Dec 4Dec 8Dec 14Dec 21Dec 26Jan 1Jan 6Jan 17
32°FDec 8Dec 16Dec 24Dec 30Jan 4Jan 9Jan 16Jan 26Feb 10
28°FDec 17Dec 26Dec 31Jan 4Jan 8Jan 13Jan 21Jan 29Feb 14
24°FDec 17Dec 22Dec 27Dec 31Jan 3Jan 6Jan 10Jan 14Jan 23
20°F–––––––––
16°F–––––––––

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°F334324313306301294287278266
32°F365357347339332324314305296
28°F365365365365365360348336322
24°F365365365365365365365365361
20°F365365365365365365365365365
16°F365365365365365365365365365

How often it gets that cold

The share of years with at least one night at or below each temperature.

36°F or colder
99% of years
32°F or colder
82% of years
28°F or colder
43% of years
24°F or colder
11% of years
20°F or colder
2% of years
16°F or colder
1% 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
439
Cooling degree days, base 65°F
3,701
Growing degree days, base 40°F
12,389
Growing degree days, base 45°F
10,568
Growing degree days, base 50°F
8,758
Growing degree days, base 55°F
6,983
Growing degree days, base 60°F
5,285

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January15068393
February8494432
March45161582
April7261704
May1416880
June0503953
July05531,018
August05611,026
September0490941
October4344805
November38155567
December11096458

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 14 km from Babson Park. 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 USC00085973 (Mtn Lake). Public domain.