Dannemora climate

Dannemora Frost Dates and Growing Season

NOAA 1991-2020 normals for Dannemora, 0.3 km from Dannemora, elevation 1340 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Dannemora. 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 6 and the first fall freeze around October 11, a growing season of about 157 days.

Median at 36°F
last May 16, first October 1
Median at 32°F
last May 6, first October 11
Median at 28°F
last April 26, first October 22

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 30May 26May 22May 19May 16May 13May 11May 7May 3
32°FMay 21May 16May 12May 9May 6May 4May 1Apr 28Apr 23
28°FMay 9May 5May 1Apr 29Apr 26Apr 23Apr 21Apr 17Apr 14
24°FApr 30Apr 25Apr 21Apr 19Apr 16Apr 13Apr 10Apr 7Apr 4
20°FApr 19Apr 15Apr 12Apr 9Apr 7Apr 5Apr 3Apr 1Mar 28
16°FApr 12Apr 7Apr 5Apr 3Apr 1Mar 31Mar 28Mar 24Mar 19

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 19Sep 23Sep 26Sep 29Oct 1Oct 2Oct 5Oct 8Oct 12
32°FSep 29Oct 2Oct 5Oct 8Oct 11Oct 13Oct 16Oct 20Oct 26
28°FOct 8Oct 13Oct 16Oct 19Oct 22Oct 25Oct 29Nov 1Nov 5
24°FOct 18Oct 23Oct 27Oct 30Nov 1Nov 4Nov 7Nov 11Nov 15
20°FOct 30Nov 2Nov 5Nov 8Nov 11Nov 14Nov 16Nov 20Nov 25
16°FNov 7Nov 11Nov 14Nov 17Nov 20Nov 23Nov 25Nov 28Dec 2

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°F154147142139136133129124118
32°F176171165161157153149145139
28°F198192186182178175171165159
24°F216211207204200197193187180
20°F235228224221217214211206201
16°F250244240236233229226222215

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
7,718
Cooling degree days, base 65°F
390
Growing degree days, base 40°F
4,149
Growing degree days, base 45°F
3,140
Growing degree days, base 50°F
2,253
Growing degree days, base 55°F
1,487
Growing degree days, base 60°F
855

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,45401
February1,24200
March1,09105
April666242
May29721225
June8773437
July19145591
August36111539
September17637320
October524285
November87309
December1,25200

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 0.3 km from Dannemora. 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 USC00301966 (Dannemora). Public domain.