Keeseville climate

Keeseville Frost Dates and Growing Season

NOAA 1991-2020 normals for S Hero, 19.5 km from Keeseville, elevation 110 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for S Hero. 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 April 28 and the first fall freeze around October 20, a growing season of about 174 days.

Median at 36°F
last May 9, first October 7
Median at 32°F
last April 28, first October 20
Median at 28°F
last April 18, first November 1

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

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 25Sep 29Oct 2Oct 5Oct 7Oct 10Oct 13Oct 17Oct 22
32°FOct 4Oct 9Oct 13Oct 16Oct 20Oct 23Oct 26Oct 29Nov 2
28°FOct 18Oct 23Oct 26Oct 30Nov 1Nov 3Nov 6Nov 8Nov 13
24°FOct 30Nov 2Nov 5Nov 8Nov 11Nov 14Nov 16Nov 19Nov 24
20°FNov 9Nov 12Nov 16Nov 18Nov 20Nov 23Nov 26Nov 28Dec 3
16°FNov 15Nov 19Nov 23Nov 26Nov 29Dec 1Dec 3Dec 7Dec 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°F169163158154150147142139132
32°F192186182177174170166161154
28°F213208204200197193189185177
24°F233227223220216213209206199
20°F249244239236232229225221214
16°F267261255251248244240235230

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
7,220
Cooling degree days, base 65°F
577
Growing degree days, base 40°F
4,543
Growing degree days, base 45°F
3,496
Growing degree days, base 50°F
2,576
Growing degree days, base 55°F
1,780
Growing degree days, base 60°F
1,105

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,40900
February1,21700
March1,05704
April632140
May26421243
June5999491
July7214673
August15181631
September12959383
October4662101
November795010
December1,17000

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 19.5 km from Keeseville. 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 USC00437607 (S Hero). Public domain.