Cortland climate

Cortland Frost Dates and Growing Season

NOAA 1991-2020 normals for Freeville 1 Ne, 15.4 km from Cortland, elevation 1050 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Freeville 1 Ne. 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 7 and the first fall freeze around October 8, a growing season of about 154 days.

Median at 36°F
last May 19, first September 29
Median at 32°F
last May 7, first October 8
Median at 28°F
last April 25, first October 24

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 26May 22May 19May 16May 12May 8May 2
32°FMay 23May 17May 13May 10May 7May 3Apr 30Apr 28Apr 23
28°FMay 10May 6May 1Apr 29Apr 25Apr 22Apr 19Apr 16Apr 11
24°FApr 30Apr 22Apr 19Apr 16Apr 13Apr 10Apr 7Apr 4Apr 1
20°FApr 15Apr 10Apr 7Apr 5Apr 3Apr 1Mar 30Mar 27Mar 21
16°FApr 6Apr 3Mar 31Mar 30Mar 27Mar 24Mar 21Mar 18Mar 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 16Sep 21Sep 24Sep 27Sep 29Oct 1Oct 3Oct 7Oct 11
32°FSep 27Oct 1Oct 3Oct 6Oct 8Oct 11Oct 14Oct 20Oct 25
28°FOct 6Oct 12Oct 16Oct 21Oct 24Oct 27Oct 30Nov 1Nov 5
24°FOct 19Oct 27Oct 31Nov 1Nov 4Nov 6Nov 9Nov 13Nov 17
20°FNov 2Nov 6Nov 10Nov 12Nov 15Nov 17Nov 21Nov 24Nov 30
16°FNov 12Nov 16Nov 19Nov 22Nov 25Nov 29Dec 2Dec 6Dec 13

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°F152146140136131128124119113
32°F174167163158154151147141134
28°F201195190186181176170164155
24°F222216212208205200196191182
20°F245237233229226222219214209
16°F265258253249245241237232226

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
7,509
Cooling degree days, base 65°F
343
Growing degree days, base 40°F
4,042
Growing degree days, base 45°F
3,023
Growing degree days, base 50°F
2,138
Growing degree days, base 55°F
1,381
Growing degree days, base 60°F
776

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,37300
February1,19401
March1,07609
April664141
May32817205
June9859413
July29134570
August5194508
September20036298
October530279
November821013
December1,14501

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 15.4 km from Cortland. Low ground, valleys and open fields freeze earlier and later than a town center or a hillside.

More

Sources

NOAA NCEI U.S. Climate Normals, 1991-2020, annual and seasonal normals for station USC00303050 (Freeville 1 Ne). Public domain.