Springfield climate

Springfield Frost Dates and Growing Season

NOAA 1991-2020 normals for Grafton, 10.4 km from Springfield, elevation 830 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Grafton. 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 2, first September 14
Median at 32°F
last May 21, first September 26
Median at 28°F
last May 8, first October 5

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 17Jun 11Jun 8Jun 5Jun 2May 31May 28May 24May 20
32°FJun 5May 31May 28May 24May 21May 18May 15May 11May 7
28°FMay 23May 18May 14May 10May 8May 5May 2Apr 30Apr 26
24°FMay 7May 2Apr 30Apr 28Apr 25Apr 22Apr 19Apr 16Apr 12
20°FApr 24Apr 20Apr 18Apr 14Apr 11Apr 9Apr 7Apr 5Apr 1
16°FApr 16Apr 10Apr 7Apr 5Apr 3Apr 1Mar 31Mar 27Mar 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°FAug 31Sep 4Sep 7Sep 11Sep 14Sep 17Sep 20Sep 24Sep 29
32°FSep 12Sep 16Sep 20Sep 23Sep 26Sep 29Oct 1Oct 3Oct 7
28°FSep 23Sep 28Oct 1Oct 2Oct 5Oct 7Oct 10Oct 14Oct 18
24°FOct 2Oct 6Oct 10Oct 13Oct 15Oct 19Oct 22Oct 27Nov 2
20°FOct 11Oct 16Oct 20Oct 25Oct 29Nov 1Nov 4Nov 9Nov 15
16°FOct 25Oct 31Nov 3Nov 7Nov 11Nov 15Nov 19Nov 24Nov 28

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°F124118112108104100969183
32°F145139134130127122118113107
28°F168161157153150146142137130
24°F194187182178174170165161155
20°F221213207203198194190185178
16°F242235230226221216212207198

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
8,180
Cooling degree days, base 65°F
261
Growing degree days, base 40°F
3,607
Growing degree days, base 45°F
2,659
Growing degree days, base 50°F
1,846
Growing degree days, base 55°F
1,163
Growing degree days, base 60°F
627

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,45200
February1,27200
March1,12701
April712125
May3846147
June13050373
July46102521
August6480480
September24022253
October608042
November89004
December1,25500

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 10.4 km from Springfield. 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 USC00273530 (Grafton). Public domain.