Halstead climate

Halstead Frost Dates and Growing Season

NOAA 1991-2020 normals for Newton, 13.7 km from Halstead, elevation 1441 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Newton. 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 14 and the first fall freeze around October 25, a growing season of about 193 days.

Median at 36°F
last April 24, first October 16
Median at 32°F
last April 14, first October 25
Median at 28°F
last April 4, first November 3

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 6May 2Apr 30Apr 26Apr 24Apr 21Apr 17Apr 14Apr 10
32°FApr 27Apr 23Apr 20Apr 17Apr 14Apr 11Apr 8Apr 4Mar 31
28°FApr 20Apr 14Apr 10Apr 7Apr 4Apr 1Mar 29Mar 25Mar 18
24°FApr 9Apr 4Mar 31Mar 28Mar 24Mar 20Mar 16Mar 11Mar 6
20°FMar 31Mar 25Mar 20Mar 16Mar 12Mar 8Mar 5Mar 2Feb 25
16°FMar 21Mar 14Mar 9Mar 5Mar 2Feb 28Feb 24Feb 19Feb 12

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 1Oct 6Oct 11Oct 14Oct 16Oct 19Oct 21Oct 24Oct 28
32°FOct 12Oct 17Oct 20Oct 23Oct 25Oct 28Oct 31Nov 2Nov 7
28°FOct 20Oct 25Oct 29Nov 1Nov 3Nov 5Nov 8Nov 12Nov 19
24°FOct 28Nov 1Nov 5Nov 8Nov 11Nov 14Nov 18Nov 23Nov 28
20°FNov 3Nov 8Nov 14Nov 18Nov 21Nov 25Nov 28Dec 1Dec 7
16°FNov 11Nov 18Nov 23Nov 27Dec 1Dec 4Dec 7Dec 14Dec 20

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°F193188182178174170165161154
32°F213207202197193190186180173
28°F236228222216212207202198191
24°F256248242237232228222215207
20°F275267262257251247241234225
16°F298289283277272266261254244

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
4,826
Cooling degree days, base 65°F
1,657
Growing degree days, base 40°F
6,871
Growing degree days, base 45°F
5,555
Growing degree days, base 50°F
4,379
Growing degree days, base 55°F
3,343
Growing degree days, base 60°F
2,438

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,05402
February834012
March617373
April32219207
May102118484
June5335780
July0493958
August1434897
September43215624
October26639280
November618159
December96404

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 13.7 km from Halstead. 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 USC00145744 (Newton). Public domain.