Mansfield climate

Mansfield Frost Dates and Growing Season

NOAA 1991-2020 normals for Champaign 9 Sw, 20.9 km from Mansfield, elevation 700 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Champaign 9 Sw. 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 23 and the first fall freeze around October 13, a growing season of about 170 days.

Median at 36°F
last May 4, first October 3
Median at 32°F
last April 23, first October 13
Median at 28°F
last April 11, first October 23

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 22May 15May 10May 6May 4Apr 30Apr 28Apr 24Apr 20
32°FMay 9May 3Apr 30Apr 25Apr 23Apr 20Apr 17Apr 13Apr 9
28°FApr 28Apr 22Apr 17Apr 14Apr 11Apr 8Apr 5Apr 2Mar 29
24°FApr 15Apr 10Apr 6Apr 2Mar 31Mar 28Mar 24Mar 20Mar 14
20°FApr 5Mar 31Mar 28Mar 24Mar 19Mar 15Mar 12Mar 8Mar 2
16°FMar 28Mar 20Mar 16Mar 13Mar 9Mar 6Mar 3Feb 27Feb 18

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 20Sep 24Sep 28Oct 1Oct 3Oct 6Oct 8Oct 11Oct 16
32°FSep 28Oct 3Oct 6Oct 10Oct 13Oct 16Oct 18Oct 22Oct 25
28°FOct 8Oct 14Oct 18Oct 21Oct 23Oct 25Oct 28Oct 31Nov 4
24°FOct 21Oct 26Oct 28Oct 31Nov 1Nov 5Nov 9Nov 14Nov 19
20°FNov 1Nov 5Nov 9Nov 12Nov 16Nov 20Nov 23Nov 28Dec 3
16°FNov 9Nov 14Nov 19Nov 23Nov 27Dec 1Dec 5Dec 9Dec 17

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°F170163159154151147143137130
32°F191183178174170166161155149
28°F214207202197193189185178171
24°F239231226221216212207202195
20°F265257251245240236231225217
16°F289278272266261256251245236

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
5,858
Cooling degree days, base 65°F
822
Growing degree days, base 40°F
5,462
Growing degree days, base 45°F
4,267
Growing degree days, base 50°F
3,208
Growing degree days, base 55°F
2,277
Growing degree days, base 60°F
1,477

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,23202
February99404
March770138
April4116140
May15570387
June17194627
July4247708
August12196649
September9590448
October37716173
November730129
December1,06203

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 20.9 km from Mansfield. 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 USW00054808 (Champaign 9 Sw). Public domain.