Leicester climate

Leicester Frost Dates and Growing Season

NOAA 1991-2020 normals for Salisbury 2 N, 6.6 km from Leicester, elevation 420 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Salisbury 2 N. 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 21 and the first fall freeze around September 26, a growing season of about 127 days.

Median at 36°F
last June 4, first September 15
Median at 32°F
last May 21, first September 26
Median at 28°F
last May 7, first October 6

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 24Jun 15Jun 10Jun 7Jun 4Jun 1May 28May 25May 19
32°FJun 7Jun 1May 28May 25May 21May 18May 15May 10May 4
28°FMay 23May 18May 14May 11May 7May 4May 1Apr 28Apr 24
24°FMay 12May 5May 1Apr 29Apr 27Apr 24Apr 21Apr 16Apr 11
20°FApr 29Apr 24Apr 21Apr 17Apr 14Apr 10Apr 7Apr 4Apr 1
16°FApr 19Apr 15Apr 10Apr 6Apr 4Apr 2Mar 31Mar 28Mar 21

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 1Sep 5Sep 9Sep 12Sep 15Sep 18Sep 21Sep 24Sep 29
32°FSep 13Sep 17Sep 21Sep 24Sep 26Sep 29Oct 1Oct 4Oct 8
28°FSep 22Sep 28Oct 1Oct 3Oct 6Oct 8Oct 11Oct 15Oct 21
24°FOct 3Oct 7Oct 11Oct 15Oct 18Oct 22Oct 26Oct 31Nov 4
20°FOct 14Oct 20Oct 25Oct 28Nov 1Nov 2Nov 6Nov 10Nov 17
16°FOct 28Nov 2Nov 5Nov 9Nov 12Nov 16Nov 20Nov 24Nov 29

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°F12211511010610197918574
32°F148140134130127123117112104
28°F169162158154149145140135128
24°F197190183178173169164159150
20°F220213208203199195190184176
16°F242235229225220216212208201

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
7,397
Cooling degree days, base 65°F
461
Growing degree days, base 40°F
4,294
Growing degree days, base 45°F
3,262
Growing degree days, base 50°F
2,361
Growing degree days, base 55°F
1,582
Growing degree days, base 60°F
940

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,40301
February1,19300
March1,03507
April622354
May28521231
June8489456
July19170615
August35132563
September16845336
October514286
November839012
December1,20101

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 6.6 km from Leicester. 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 USC00437098 (Salisbury 2 N). Public domain.