Greenfield climate

Greenfield Frost Dates and Growing Season

NOAA 1991-2020 normals for Greenville 1 Nne, 19.6 km from Greenfield, elevation 900 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Greenville 1 Nne. 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 10 and the first fall freeze around October 6, a growing season of about 147 days.

Median at 36°F
last May 23, first September 28
Median at 32°F
last May 10, first October 6
Median at 28°F
last April 26, first October 18

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

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 13Sep 18Sep 22Sep 25Sep 28Sep 30Oct 1Oct 4Oct 8
32°FSep 25Sep 29Oct 1Oct 3Oct 6Oct 8Oct 11Oct 15Oct 21
28°FOct 2Oct 7Oct 10Oct 15Oct 18Oct 21Oct 25Oct 30Nov 3
24°FOct 16Oct 21Oct 26Oct 29Nov 1Nov 4Nov 7Nov 12Nov 19
20°FOct 28Nov 2Nov 6Nov 10Nov 14Nov 18Nov 23Nov 28Dec 2
16°FNov 11Nov 17Nov 22Nov 25Nov 28Dec 1Dec 3Dec 7Dec 12

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°F145138133129125121117112105
32°F168161156151147144140135128
28°F198189183178174169165159152
24°F226218214209204200195189182
20°F251244238234229224220215207
16°F273264259254249245241236229

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
7,352
Cooling degree days, base 65°F
342
Growing degree days, base 40°F
4,008
Growing degree days, base 45°F
2,986
Growing degree days, base 50°F
2,103
Growing degree days, base 55°F
1,359
Growing degree days, base 60°F
764

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,32400
February1,13400
March1,02607
April639142
May34010178
June11754392
July25143582
August4498519
September19736299
October534170
November813013
December1,16101

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 19.6 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 USC00273658 (Greenville 1 Nne). Public domain.