Presho climate

Presho Frost Dates and Growing Season

NOAA 1991-2020 normals for Kennebec, 16.1 km from Presho, elevation 1681 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Kennebec. 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 12 and the first fall freeze around September 28, a growing season of about 137 days.

Median at 36°F
last May 21, first September 20
Median at 32°F
last May 12, first September 28
Median at 28°F
last May 3, 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 2May 29May 26May 24May 21May 18May 15May 12May 8
32°FMay 26May 21May 17May 14May 12May 9May 7May 4Apr 29
28°FMay 17May 12May 8May 5May 3Apr 30Apr 27Apr 24Apr 19
24°FMay 7May 2Apr 29Apr 26Apr 24Apr 20Apr 17Apr 13Apr 8
20°FApr 28Apr 24Apr 19Apr 16Apr 13Apr 10Apr 7Apr 3Mar 29
16°FApr 20Apr 15Apr 11Apr 7Apr 4Apr 1Mar 29Mar 23Mar 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 6Sep 12Sep 16Sep 18Sep 20Sep 23Sep 26Sep 29Oct 3
32°FSep 15Sep 19Sep 23Sep 25Sep 28Oct 1Oct 3Oct 6Oct 10
28°FSep 21Sep 27Sep 30Oct 3Oct 5Oct 8Oct 11Oct 14Oct 18
24°FOct 1Oct 5Oct 8Oct 12Oct 14Oct 17Oct 20Oct 24Oct 29
20°FOct 10Oct 14Oct 18Oct 21Oct 25Oct 28Oct 31Nov 3Nov 7
16°FOct 19Oct 25Oct 29Nov 1Nov 3Nov 6Nov 9Nov 12Nov 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°F139132128124120116112107100
32°F155149145140137133130125119
28°F174167162158154150146141135
24°F194186182178174170165159153
20°F213206201197193189185180173
16°F235227221216212207202197190

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
7,042
Cooling degree days, base 65°F
929
Growing degree days, base 40°F
5,129
Growing degree days, base 45°F
4,045
Growing degree days, base 50°F
3,084
Growing degree days, base 55°F
2,245
Growing degree days, base 60°F
1,522

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,38300
February1,13201
March904019
April536386
May23841295
June40160570
July5332792
August13276728
September111108453
October4839127
November909011
December1,28900

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 16.1 km from Presho. 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 USC00394516 (Kennebec). Public domain.