Whitehall climate

Whitehall Frost Dates and Growing Season

NOAA 1991-2020 normals for Montague 4 Nw, 8 km from Whitehall, elevation 650 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Montague 4 Nw. 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 19 and the first fall freeze around October 4, a growing season of about 136 days.

Median at 36°F
last May 31, first September 23
Median at 32°F
last May 19, first October 4
Median at 28°F
last May 5, 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 22Jun 12Jun 7Jun 3May 31May 28May 25May 22May 15
32°FJun 6May 31May 27May 23May 19May 15May 11May 7May 1
28°FMay 26May 18May 13May 9May 5May 1Apr 29Apr 25Apr 19
24°FMay 10May 3Apr 28Apr 25Apr 21Apr 18Apr 14Apr 10Apr 5
20°FApr 24Apr 19Apr 16Apr 12Apr 8Apr 5Apr 2Mar 30Mar 24
16°FApr 11Apr 5Apr 2Mar 31Mar 28Mar 24Mar 21Mar 17Mar 11

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 1Sep 9Sep 13Sep 18Sep 23Sep 27Oct 1Oct 3Oct 7
32°FSep 16Sep 22Sep 27Oct 1Oct 4Oct 7Oct 10Oct 15Oct 20
28°FSep 30Oct 5Oct 10Oct 14Oct 18Oct 21Oct 25Oct 30Nov 4
24°FOct 16Oct 23Oct 28Nov 1Nov 2Nov 6Nov 9Nov 15Nov 22
20°FNov 1Nov 6Nov 11Nov 16Nov 20Nov 24Nov 28Dec 2Dec 8
16°FNov 16Nov 23Nov 28Dec 2Dec 5Dec 9Dec 14Dec 20Dec 26

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°F1351271211171121061009280
32°F162153147141136132127121112
28°F190181175171165159154147138
24°F220212205199194190184177167
20°F252242236231225219213207197
16°F275268262257252246241236227

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
6,941
Cooling degree days, base 65°F
400
Growing degree days, base 40°F
4,237
Growing degree days, base 45°F
3,185
Growing degree days, base 50°F
2,270
Growing degree days, base 55°F
1,491
Growing degree days, base 60°F
857

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,25900
February1,10300
March975010
April610147
May32316200
June9373432
July31144578
August38117544
September16045342
October4714102
November785014
December1,09401

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 8 km from Whitehall. 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 USC00205567 (Montague 4 Nw). Public domain.