Herkimer climate

Herkimer Frost Dates and Growing Season

NOAA 1991-2020 normals for Little Falls City Rsch, 10.3 km from Herkimer, elevation 893 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Little Falls City Rsch. 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 4, a growing season of about 151 days.

Median at 36°F
last May 17, first September 24
Median at 32°F
last May 5, first October 4
Median at 28°F
last April 26, first October 16

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 11May 8May 4
32°FMay 20May 16May 11May 8May 5May 3Apr 30Apr 28Apr 24
28°FMay 9May 4May 1Apr 29Apr 26Apr 23Apr 20Apr 18Apr 13
24°FApr 26Apr 21Apr 19Apr 17Apr 15Apr 12Apr 9Apr 6Apr 3
20°FApr 17Apr 13Apr 10Apr 7Apr 5Apr 4Apr 2Mar 31Mar 26
16°FApr 9Apr 5Apr 3Apr 1Mar 31Mar 28Mar 25Mar 21Mar 17

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

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°F148142138133130126122118111
32°F170163159155151147143138133
28°F195188183178174170166161153
24°F217211207203200196192186178
20°F238231226222218215211206201
16°F256249244239235232228224218

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
7,470
Cooling degree days, base 65°F
410
Growing degree days, base 40°F
4,186
Growing degree days, base 45°F
3,167
Growing degree days, base 50°F
2,275
Growing degree days, base 55°F
1,509
Growing degree days, base 60°F
880

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,39001
February1,20700
March1,08406
April660243
May30119215
June8383451
July17156604
August35116546
September17133320
October512282
November83008
December1,18102

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 10.3 km from Herkimer. 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 USC00304791 (Little Falls City Rsch). Public domain.