Good Thunder climate

Good Thunder Frost Dates and Growing Season

NOAA 1991-2020 normals for Amboy, 15.7 km from Good Thunder, elevation 1030 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Amboy. 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 7, a growing season of about 161 days.

Median at 36°F
last May 8, first September 30
Median at 32°F
last April 30, first October 7
Median at 28°F
last April 20, first October 20

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 21May 16May 13May 10May 8May 5May 2Apr 30Apr 25
32°FMay 12May 7May 4May 2Apr 30Apr 27Apr 24Apr 20Apr 14
28°FMay 4Apr 30Apr 26Apr 23Apr 20Apr 16Apr 12Apr 8Apr 3
24°FApr 26Apr 21Apr 16Apr 12Apr 9Apr 6Apr 3Mar 31Mar 25
20°FApr 18Apr 11Apr 6Apr 4Apr 1Mar 29Mar 25Mar 20Mar 15
16°FApr 10Apr 4Mar 31Mar 27Mar 22Mar 18Mar 15Mar 12Mar 8

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 16Sep 20Sep 24Sep 27Sep 30Oct 2Oct 4Oct 7Oct 12
32°FSep 23Sep 28Oct 1Oct 4Oct 7Oct 11Oct 14Oct 18Oct 22
28°FOct 3Oct 8Oct 13Oct 16Oct 20Oct 22Oct 25Oct 29Nov 1
24°FOct 15Oct 21Oct 25Oct 27Oct 30Nov 1Nov 3Nov 7Nov 11
20°FOct 25Oct 31Nov 2Nov 4Nov 7Nov 9Nov 12Nov 16Nov 22
16°FNov 2Nov 6Nov 9Nov 12Nov 14Nov 17Nov 21Nov 25Nov 30

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°F161155150147143139135131124
32°F180174169165161156152147140
28°F203196191187182178173168161
24°F225217212208203199195189181
20°F242234229224220216212206198
16°F258251245240236231227222216

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
7,257
Cooling degree days, base 65°F
812
Growing degree days, base 40°F
5,029
Growing degree days, base 45°F
3,964
Growing degree days, base 50°F
3,001
Growing degree days, base 55°F
2,150
Growing degree days, base 60°F
1,417

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,49100
February1,22600
March975116
April520597
May19559344
June26194618
July7266724
August15192642
September12386419
October46511130
November891012
December1,32200

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 15.7 km from Good Thunder. 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 USC00210157 (Amboy). Public domain.