Champlain climate

Champlain Frost Dates and Growing Season

NOAA 1991-2020 normals for Chazy, 12.6 km from Champlain, elevation 157 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Chazy. 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 30 and the first fall freeze around October 12, a growing season of about 164 days.

Median at 36°F
last May 11, first October 1
Median at 32°F
last April 30, first October 12
Median at 28°F
last April 19, first October 25

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

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°F161154150146142139134130122
32°F184177173168164161155151144
28°F207201196193189184180175166
24°F227222217213210207204199192
20°F247240235231228224220216212
16°F261256251247243238235230224

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
7,126
Cooling degree days, base 65°F
601
Growing degree days, base 40°F
4,653
Growing degree days, base 45°F
3,585
Growing degree days, base 50°F
2,648
Growing degree days, base 55°F
1,835
Growing degree days, base 60°F
1,145

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,41700
February1,22100
March1,03203
April579357
May23026274
June47115518
July5227686
August17175623
September13752370
October4653104
November795012
December1,18001

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 12.6 km from Champlain. 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 USC00301401 (Chazy). Public domain.