Cornell climate

Cornell Frost Dates and Growing Season

NOAA 1991-2020 normals for Holcombe, 6.5 km from Cornell, elevation 1057 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Holcombe. 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 5 and the first fall freeze around October 2, a growing season of about 149 days.

Median at 36°F
last May 18, first September 24
Median at 32°F
last May 5, first October 2
Median at 28°F
last April 24, first October 14

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 1May 28May 24May 21May 18May 15May 12May 8May 5
32°FMay 21May 16May 12May 8May 5May 3Apr 30Apr 26Apr 21
28°FMay 9May 3Apr 30Apr 27Apr 24Apr 21Apr 18Apr 14Apr 10
24°FApr 28Apr 22Apr 19Apr 15Apr 12Apr 9Apr 6Apr 3Mar 31
20°FApr 19Apr 12Apr 9Apr 6Apr 4Apr 2Mar 31Mar 27Mar 22
16°FApr 11Apr 6Apr 3Apr 1Mar 31Mar 28Mar 24Mar 20Mar 14

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 10Sep 14Sep 18Sep 21Sep 24Sep 27Sep 30Oct 2Oct 6
32°FSep 19Sep 24Sep 28Oct 1Oct 2Oct 5Oct 8Oct 12Oct 17
28°FSep 29Oct 2Oct 6Oct 10Oct 14Oct 17Oct 21Oct 25Oct 30
24°FOct 8Oct 16Oct 20Oct 23Oct 26Oct 29Nov 1Nov 5Nov 10
20°FOct 22Oct 29Nov 1Nov 3Nov 6Nov 9Nov 12Nov 17Nov 21
16°FOct 31Nov 4Nov 8Nov 12Nov 15Nov 18Nov 21Nov 25Dec 1

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°F147141137133129125122117110
32°F169162158153149145140135128
28°F195188182177172168163157149
24°F215209204200195191187181174
20°F235227222218214211207203195
16°F250243238234229225221217211

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
8,453
Cooling degree days, base 65°F
376
Growing degree days, base 40°F
3,976
Growing degree days, base 45°F
3,005
Growing degree days, base 50°F
2,152
Growing degree days, base 55°F
1,420
Growing degree days, base 60°F
820

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,63400
February1,35700
March1,12506
April663038
May31415206
June8475442
July21150594
August44103524
September21931281
October593258
November99504
December1,40600

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 6.5 km from Cornell. 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 USC00473698 (Holcombe). Public domain.