Johnsonburg climate

Johnsonburg Frost Dates and Growing Season

NOAA 1991-2020 normals for Glen Hazel 2 Ne Dam, 10 km from Johnsonburg, elevation 1720 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Glen Hazel 2 Ne Dam. 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 14 and the first fall freeze around October 6, a growing season of about 143 days.

Median at 36°F
last May 27, first September 27
Median at 32°F
last May 14, first October 6
Median at 28°F
last May 3, first October 18

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°FJun 8Jun 3Jun 1May 30May 27May 24May 22May 17May 11
32°FMay 29May 24May 21May 17May 14May 10May 7May 3Apr 28
28°FMay 19May 14May 10May 6May 3Apr 30Apr 26Apr 23Apr 18
24°FMay 9May 2Apr 27Apr 23Apr 20Apr 18Apr 15Apr 11Apr 7
20°FApr 22Apr 17Apr 13Apr 10Apr 7Apr 4Apr 2Mar 31Mar 25
16°FApr 10Apr 5Apr 2Mar 31Mar 29Mar 25Mar 22Mar 18Mar 13

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

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°F140134129125121117114109101
32°F163157152147143139135130123
28°F190183177173168163159153146
24°F214206201198193189183178169
20°F242232228224219216210205198
16°F263254249245241237233228221

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
7,466
Cooling degree days, base 65°F
250
Growing degree days, base 40°F
3,934
Growing degree days, base 45°F
2,900
Growing degree days, base 50°F
2,008
Growing degree days, base 55°F
1,253
Growing degree days, base 60°F
655

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,33901
February1,16501
March1,03208
April640144
May33211194
June11345385
July4195519
August5572482
September19524288
October534278
November84607
December1,17501

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 km from Johnsonburg. 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 USC00363311 (Glen Hazel 2 Ne Dam). Public domain.