Bedford climate

Bedford Frost Dates and Growing Season

NOAA 1991-2020 normals for Manchester AP, 6.5 km from Bedford, elevation 225 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Manchester 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 19, a growing season of about 180 days.

Median at 36°F
last May 4, first October 7
Median at 32°F
last April 21, first October 19
Median at 28°F
last April 7, first November 1

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 19May 14May 9May 6May 4May 1Apr 29Apr 26Apr 23
32°FMay 6May 1Apr 27Apr 24Apr 21Apr 19Apr 16Apr 13Apr 8
28°FApr 21Apr 17Apr 13Apr 10Apr 7Apr 5Apr 3Apr 1Mar 28
24°FApr 7Apr 3Apr 1Mar 31Mar 29Mar 26Mar 22Mar 19Mar 15
20°FMar 31Mar 28Mar 25Mar 21Mar 19Mar 16Mar 13Mar 10Mar 6
16°FMar 25Mar 20Mar 16Mar 14Mar 11Mar 9Mar 6Mar 2Feb 26

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

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°F172166162159156153149144139
32°F198192187184180176172168160
28°F224219214209206203198193186
24°F250243238233230226222217212
20°F272265260255251248244239232
16°F290283278274270266262257251

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
6,172
Cooling degree days, base 65°F
773
Growing degree days, base 40°F
5,087
Growing degree days, base 45°F
3,943
Growing degree days, base 50°F
2,943
Growing degree days, base 55°F
2,079
Growing degree days, base 60°F
1,357

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,22100
February1,03001
March884113
April509577
May22233288
June46141545
July3278739
August7232690
September9879432
October4036134
November707023
December1,04202

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 6.5 km from Bedford. 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 USW00014710 (Manchester AP). Public domain.