Greenfield climate

Greenfield Frost Dates and Growing Season

NOAA 1991-2020 normals for White Hall 1 E, 17.9 km from Greenfield, elevation 580 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for White Hall 1 E. 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 13 and the first fall freeze around October 22, a growing season of about 190 days.

Median at 36°F
last April 25, first October 12
Median at 32°F
last April 13, first October 22
Median at 28°F
last April 2, 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 9May 4May 1Apr 28Apr 25Apr 22Apr 18Apr 15Apr 11
32°FApr 28Apr 23Apr 20Apr 16Apr 13Apr 10Apr 7Apr 3Mar 30
28°FApr 17Apr 11Apr 7Apr 4Apr 2Mar 31Mar 27Mar 23Mar 16
24°FApr 6Apr 1Mar 29Mar 25Mar 22Mar 19Mar 15Mar 11Mar 5
20°FMar 28Mar 23Mar 18Mar 15Mar 12Mar 9Mar 5Mar 2Feb 23
16°FMar 21Mar 16Mar 12Mar 8Mar 5Mar 2Feb 27Feb 21Feb 12

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 29Oct 3Oct 7Oct 10Oct 12Oct 15Oct 18Oct 21Oct 24
32°FOct 9Oct 14Oct 17Oct 19Oct 22Oct 24Oct 27Oct 29Nov 2
28°FOct 19Oct 24Oct 27Oct 30Nov 1Nov 3Nov 5Nov 9Nov 14
24°FOct 29Nov 1Nov 5Nov 8Nov 11Nov 14Nov 17Nov 22Nov 27
20°FNov 5Nov 10Nov 14Nov 18Nov 21Nov 25Nov 30Dec 3Dec 9
16°FNov 14Nov 20Nov 25Nov 29Dec 1Dec 5Dec 10Dec 15Dec 21

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°F188182178173169165161157151
32°F210203198194190186182177170
28°F233225220215211207203198191
24°F257248243238233229224218210
20°F279271264258253248243237229
16°F300291284279273268263256248

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
5,477
Cooling degree days, base 65°F
1,107
Growing degree days, base 40°F
5,970
Growing degree days, base 45°F
4,737
Growing degree days, base 50°F
3,639
Growing degree days, base 55°F
2,664
Growing degree days, base 60°F
1,816

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,18102
February94605
March727248
April37413169
May13186425
June14236672
July2332795
August4283744
September71131512
October33124216
November678147
December1,02005

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 17.9 km from Greenfield. 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 USC00119241 (White Hall 1 E). Public domain.