Potsdam climate

Potsdam Frost Dates and Growing Season

NOAA 1991-2020 normals for Colton 2 N, 9.7 km from Potsdam, elevation 580 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Colton 2 N. 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 8, a growing season of about 156 days.

Median at 36°F
last May 17, first September 28
Median at 32°F
last May 5, first October 8
Median at 28°F
last April 24, 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 27May 23May 20May 17May 14May 10May 6May 1
32°FMay 21May 16May 12May 8May 5May 2Apr 29Apr 26Apr 22
28°FMay 9May 4Apr 30Apr 27Apr 24Apr 22Apr 19Apr 15Apr 10
24°FApr 24Apr 20Apr 17Apr 15Apr 12Apr 9Apr 6Apr 4Apr 2
20°FApr 16Apr 12Apr 7Apr 5Apr 4Apr 2Mar 31Mar 29Mar 23
16°FApr 8Apr 4Apr 2Apr 1Mar 30Mar 28Mar 24Mar 20Mar 16

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

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°F153147143138134129124120112
32°F178171165161156152148143135
28°F203195189185181176172166160
24°F225219214210207202198193186
20°F243237232229225221218213206
16°F257251247243239236232228222

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
8,038
Cooling degree days, base 65°F
397
Growing degree days, base 40°F
4,067
Growing degree days, base 45°F
3,079
Growing degree days, base 50°F
2,219
Growing degree days, base 55°F
1,476
Growing degree days, base 60°F
853

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,51800
February1,30000
March1,155010
April690138
May31819218
June9382441
July23145587
August36112541
September20538300
October542176
November88208
December1,27700

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 9.7 km from Potsdam. 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 USC00301664 (Colton 2 N). Public domain.