Strong climate

Strong Frost Dates and Growing Season

NOAA 1991-2020 normals for Calion L&d, 26 km from Strong, elevation 77 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Calion L&d. 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 March 18 and the first fall freeze around November 7, a growing season of about 235 days.

Median at 36°F
last April 2, first October 30
Median at 32°F
last March 18, first November 7
Median at 28°F
last March 4, first November 21

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°FApr 20Apr 13Apr 7Apr 5Apr 2Mar 30Mar 26Mar 20Mar 14
32°FApr 6Apr 1Mar 27Mar 22Mar 18Mar 15Mar 10Mar 6Feb 28
28°FMar 23Mar 16Mar 11Mar 8Mar 4Feb 28Feb 26Feb 21Feb 10
24°FMar 10Mar 4Feb 28Feb 23Feb 17Feb 12Feb 2Jan 29Jan 19
20°FFeb 27Feb 15Feb 8Feb 2Jan 31Jan 25Jan 19Jan 10Dec 30
16°FFeb 8Feb 1Jan 28Jan 23Jan 19Jan 11Jan 6Dec 31Dec 24

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°FOct 16Oct 20Oct 23Oct 26Oct 30Nov 1Nov 4Nov 7Nov 13
32°FOct 24Oct 30Nov 2Nov 5Nov 7Nov 11Nov 15Nov 19Nov 27
28°FNov 3Nov 7Nov 12Nov 16Nov 21Nov 26Dec 1Dec 4Dec 11
24°FNov 12Nov 19Nov 26Dec 1Dec 5Dec 10Dec 19Dec 28Jan 5
20°FNov 27Dec 6Dec 14Dec 21Dec 27Jan 1Jan 6Jan 14Jan 25
16°FDec 12Dec 22Dec 27Jan 1Jan 4Jan 8Jan 15Jan 20Feb 1

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°F232224219214210206202196188
32°F260251245240235230225219209
28°F290279272266262256251244235
24°F331319310303296289280273261
20°F365354346337331324317308297
16°F365365365365365360349341331

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
99% of years
20°F or colder
87% of years
16°F or colder
50% 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
2,754
Cooling degree days, base 65°F
2,124
Growing degree days, base 40°F
8,655
Growing degree days, base 45°F
7,045
Growing degree days, base 50°F
5,579
Growing degree days, base 55°F
4,268
Growing degree days, base 60°F
3,116

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January668147
February501373
March32416208
April12863391
May20212657
June1402852
July0521986
August0499964
September9309750
October12784429
November37612157
December601366

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 26 km from Strong. 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 USC00031140 (Calion L&d). Public domain.