Mansfield climate

Mansfield Frost Dates and Growing Season

NOAA 1991-2020 normals for Tioga Hammond Dam, 11.4 km from Mansfield, elevation 1230 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Tioga Hammond Dam. 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 6 and the first fall freeze around October 10, a growing season of about 158 days.

Median at 36°F
last May 19, first October 1
Median at 32°F
last May 6, first October 10
Median at 28°F
last April 26, first October 26

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 31May 28May 25May 22May 19May 15May 11May 8May 2
32°FMay 23May 17May 12May 9May 6May 3Apr 30Apr 28Apr 24
28°FMay 11May 5May 1Apr 29Apr 26Apr 23Apr 20Apr 17Apr 13
24°FApr 30Apr 23Apr 19Apr 16Apr 14Apr 11Apr 7Apr 4Mar 31
20°FApr 15Apr 10Apr 6Apr 4Apr 2Mar 31Mar 29Mar 26Mar 20
16°FApr 5Apr 2Mar 31Mar 29Mar 26Mar 22Mar 19Mar 15Mar 10

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 18Sep 22Sep 26Sep 29Oct 1Oct 3Oct 5Oct 9Oct 13
32°FSep 30Oct 1Oct 4Oct 6Oct 10Oct 14Oct 18Oct 22Oct 28
28°FOct 5Oct 12Oct 17Oct 22Oct 26Oct 30Nov 1Nov 5Nov 10
24°FOct 23Oct 29Nov 1Nov 5Nov 8Nov 11Nov 14Nov 17Nov 22
20°FNov 6Nov 10Nov 14Nov 17Nov 20Nov 23Nov 27Dec 1Dec 6
16°FNov 14Nov 19Nov 23Nov 27Nov 30Dec 2Dec 6Dec 11Dec 18

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°F155149143138135131127122115
32°F179172167162158154149144136
28°F203196191187183178173168159
24°F229222216212208204199193185
20°F252245240235231227223218211
16°F275266260255251247242238231

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
6,945
Cooling degree days, base 65°F
441
Growing degree days, base 40°F
4,367
Growing degree days, base 45°F
3,305
Growing degree days, base 50°F
2,382
Growing degree days, base 55°F
1,589
Growing degree days, base 60°F
931

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,28200
February1,11801
March99808
April607152
May28920233
June7379457
July17161609
August27128566
September16347341
October486499
November786016
December1,09901

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 11.4 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 USC00368868 (Tioga Hammond Dam). Public domain.