Mandaree climate

Mandaree Frost Dates and Growing Season

NOAA 1991-2020 normals for Keene 3S, 26.1 km from Mandaree, elevation 2470 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Keene 3S. 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 20 and the first fall freeze around September 20, a growing season of about 121 days.

Median at 36°F
last May 30, first September 11
Median at 32°F
last May 20, first September 20
Median at 28°F
last May 10, first September 28

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 20Jun 12Jun 5Jun 2May 30May 27May 25May 22May 17
32°FJun 2May 28May 25May 22May 20May 17May 15May 12May 8
28°FMay 24May 19May 15May 13May 10May 7May 5May 2Apr 27
24°FMay 13May 9May 5May 3Apr 30Apr 28Apr 25Apr 20Apr 15
20°FMay 4Apr 30Apr 26Apr 23Apr 19Apr 16Apr 13Apr 9Apr 4
16°FApr 26Apr 20Apr 16Apr 13Apr 9Apr 6Apr 4Apr 1Mar 25

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°FAug 27Sep 2Sep 4Sep 8Sep 11Sep 14Sep 17Sep 20Sep 23
32°FSep 5Sep 9Sep 14Sep 17Sep 20Sep 22Sep 25Sep 28Oct 2
28°FSep 13Sep 18Sep 22Sep 25Sep 28Oct 1Oct 4Oct 8Oct 14
24°FSep 22Sep 28Oct 2Oct 6Oct 9Oct 12Oct 15Oct 19Oct 24
20°FOct 4Oct 9Oct 13Oct 16Oct 19Oct 22Oct 26Oct 30Nov 3
16°FOct 12Oct 17Oct 22Oct 25Oct 28Oct 31Nov 3Nov 7Nov 12

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°F12111511010610297928475
32°F140134130125121118113108101
28°F160153148145141137133128121
24°F180173168164160156152147139
20°F202194189184180175172166160
16°F222213208203199194190184177

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
8,679
Cooling degree days, base 65°F
435
Growing degree days, base 40°F
3,978
Growing degree days, base 45°F
3,016
Growing degree days, base 50°F
2,176
Growing degree days, base 55°F
1,453
Growing degree days, base 60°F
870

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,60900
February1,33100
March1,10205
April667143
May35112187
June11356396
July31161595
August44161583
September22143298
October645264
November1,07905
December1,48600

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 26.1 km from Mandaree. 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 USC00324571 (Keene 3S). Public domain.