Mansfield climate

Mansfield Frost Dates and Growing Season

NOAA 1991-2020 normals for Mansfield 4 Nw, 6.7 km from Mansfield, elevation 322 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Mansfield 4 Nw. 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 March 8 and the first fall freeze around November 20, a growing season of about 255 days.

Median at 36°F
last March 26, first November 9
Median at 32°F
last March 8, first November 20
Median at 28°F
last February 22, first December 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°FApr 15Apr 8Apr 4Mar 31Mar 26Mar 21Mar 16Mar 11Mar 1
32°FApr 1Mar 25Mar 18Mar 12Mar 8Mar 4Feb 28Feb 22Feb 13
28°FMar 16Mar 9Mar 3Feb 28Feb 22Feb 15Feb 5Jan 31Jan 22
24°FMar 5Feb 26Feb 14Feb 6Jan 31Jan 28Jan 22Jan 12Dec 31
20°FFeb 20Feb 7Feb 1Jan 28Jan 22Jan 15Jan 9Dec 31Dec 17
16°FFeb 9Feb 2Jan 26Jan 18Jan 11Jan 3Dec 28Dec 19Dec 11

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°FOct 27Nov 1Nov 3Nov 5Nov 9Nov 12Nov 16Nov 22Nov 28
32°FNov 2Nov 7Nov 12Nov 15Nov 20Nov 24Nov 30Dec 3Dec 8
28°FNov 10Nov 16Nov 21Nov 28Dec 1Dec 5Dec 10Dec 18Jan 1
24°FNov 21Dec 1Dec 5Dec 11Dec 18Dec 28Jan 2Jan 9Jan 20
20°FDec 1Dec 11Dec 18Dec 27Jan 1Jan 7Jan 14Jan 21Feb 3
16°FDec 10Dec 16Dec 24Dec 31Jan 5Jan 10Jan 17Jan 29Feb 6

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°F256246240234228223217212204
32°F287276266260255250243236227
28°F322310302293287278271261252
24°F360344336328320312304293280
20°F365365365362352345335327311
16°F365365365365365365365355339

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
93% of years
20°F or colder
63% of years
16°F or colder
26% 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
2,215
Cooling degree days, base 65°F
2,416
Growing degree days, base 40°F
9,418
Growing degree days, base 45°F
7,740
Growing degree days, base 50°F
6,174
Growing degree days, base 55°F
4,758
Growing degree days, base 60°F
3,501

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January572584
February39210128
March24429276
April9981434
May13249701
June0450900
July05501,015
August05471,012
September3341787
October77129519
November29717216
December5189103

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 6.7 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 USC00165874 (Mansfield 4 Nw). Public domain.