Minto climate

Minto Frost Dates and Growing Season

NOAA 1991-2020 normals for Grafton, 14.6 km from Minto, elevation 827 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 4 and the first fall freeze around October 7, a growing season of about 156 days.

Median at 36°F
last May 13, first September 28
Median at 32°F
last May 4, first October 7
Median at 28°F
last April 24, first October 17

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 26May 22May 18May 15May 13May 10May 7May 4Apr 30
32°FMay 18May 13May 9May 6May 4May 1Apr 28Apr 24Apr 19
28°FMay 9May 4Apr 30Apr 27Apr 24Apr 21Apr 18Apr 14Apr 9
24°FApr 30Apr 25Apr 22Apr 19Apr 15Apr 12Apr 9Apr 5Apr 1
20°FApr 23Apr 18Apr 14Apr 10Apr 8Apr 5Apr 2Mar 30Mar 23
16°FApr 16Apr 10Apr 7Apr 4Apr 2Mar 31Mar 26Mar 22Mar 17

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 17Sep 21Sep 24Sep 27Sep 28Oct 1Oct 3Oct 6Oct 10
32°FSep 25Sep 29Oct 1Oct 4Oct 7Oct 10Oct 12Oct 17Oct 21
28°FOct 3Oct 7Oct 11Oct 14Oct 17Oct 20Oct 23Oct 26Oct 30
24°FOct 12Oct 16Oct 20Oct 23Oct 26Oct 30Nov 1Nov 4Nov 8
20°FOct 20Oct 26Oct 29Nov 1Nov 3Nov 5Nov 8Nov 11Nov 16
16°FOct 28Nov 1Nov 4Nov 6Nov 9Nov 12Nov 15Nov 18Nov 23

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°F155149145141138135131127121
32°F176167163160156152148143137
28°F196189183179174170166162154
24°F212205201197193189185180172
20°F228221216213208205201196189
16°F242236231226222218214209203

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
8,950
Cooling degree days, base 65°F
611
Growing degree days, base 40°F
4,323
Growing degree days, base 45°F
3,376
Growing degree days, base 50°F
2,527
Growing degree days, base 55°F
1,774
Growing degree days, base 60°F
1,126

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,77600
February1,46700
March1,19501
April668248
May27736275
June51139539
July12206659
August31173607
September18452332
October620364
November1,08903
December1,58100

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 14.6 km from Minto. 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 USC00323594 (Grafton). Public domain.