Longmeadow climate

Longmeadow Frost Dates and Growing Season

NOAA 1991-2020 normals for Hartford Bradley Intl AP, 14.9 km from Longmeadow, elevation 190 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Hartford Bradley Intl 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 21 and the first fall freeze around October 16, a growing season of about 177 days.

Median at 36°F
last May 5, first October 6
Median at 32°F
last April 21, first October 16
Median at 28°F
last April 7, first October 29

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 18May 14May 11May 8May 5May 2Apr 30Apr 27Apr 22
32°FMay 6May 1Apr 27Apr 24Apr 21Apr 19Apr 16Apr 12Apr 8
28°FApr 22Apr 17Apr 13Apr 9Apr 7Apr 4Apr 2Mar 31Mar 26
24°FApr 7Apr 3Apr 1Mar 31Mar 28Mar 25Mar 22Mar 19Mar 14
20°FMar 31Mar 28Mar 24Mar 21Mar 18Mar 16Mar 13Mar 9Mar 3
16°FMar 24Mar 20Mar 17Mar 13Mar 10Mar 7Mar 3Feb 28Feb 23

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 1Oct 4Oct 6Oct 8Oct 11Oct 15Oct 21
32°FOct 3Oct 7Oct 10Oct 13Oct 16Oct 19Oct 23Oct 27Nov 2
28°FOct 13Oct 18Oct 22Oct 26Oct 29Nov 1Nov 3Nov 6Nov 12
24°FOct 27Nov 1Nov 4Nov 7Nov 11Nov 14Nov 17Nov 20Nov 26
20°FNov 8Nov 13Nov 17Nov 20Nov 23Nov 26Nov 30Dec 3Dec 9
16°FNov 20Nov 26Nov 30Dec 2Dec 5Dec 8Dec 12Dec 17Dec 24

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°F172165160156153149146141135
32°F198192186181177173169164157
28°F223216212208204200195190184
24°F250242237232228224219215208
20°F272265259254250245241236230
16°F294287280275271267262257249

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
5,883
Cooling degree days, base 65°F
819
Growing degree days, base 40°F
5,277
Growing degree days, base 45°F
4,100
Growing degree days, base 50°F
3,069
Growing degree days, base 55°F
2,178
Growing degree days, base 60°F
1,424

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,17601
February99101
March845014
April473793
May19340318
June35150566
July2290753
August6238697
September9386444
October3828152
November683028
December1,00403

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 14.9 km from Longmeadow. 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 USW00014740 (Hartford Bradley Intl AP). Public domain.