Huron climate

Huron Frost Dates and Growing Season

NOAA 1991-2020 normals for Huron Rgnl AP, 4 km from Huron, elevation 1280 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Huron Rgnl AP. 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 6 and the first fall freeze around October 2, a growing season of about 146 days.

Median at 36°F
last May 16, first September 24
Median at 32°F
last May 6, first October 2
Median at 28°F
last April 27, first October 8

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 28May 24May 21May 19May 16May 14May 10May 7May 3
32°FMay 20May 15May 12May 9May 6May 4May 1Apr 28Apr 23
28°FMay 11May 5May 2Apr 30Apr 27Apr 24Apr 20Apr 17Apr 12
24°FMay 2Apr 27Apr 23Apr 20Apr 16Apr 13Apr 11Apr 7Apr 4
20°FApr 23Apr 17Apr 13Apr 10Apr 7Apr 4Apr 2Mar 30Mar 23
16°FApr 15Apr 8Apr 4Apr 1Mar 29Mar 26Mar 22Mar 17Mar 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°FSep 10Sep 15Sep 19Sep 22Sep 24Sep 27Sep 29Oct 2Oct 5
32°FSep 19Sep 23Sep 27Sep 30Oct 2Oct 4Oct 7Oct 10Oct 14
28°FSep 26Sep 30Oct 2Oct 5Oct 8Oct 11Oct 14Oct 18Oct 22
24°FOct 4Oct 8Oct 12Oct 16Oct 19Oct 22Oct 24Oct 28Nov 1
20°FOct 12Oct 18Oct 22Oct 26Oct 28Oct 31Nov 3Nov 6Nov 12
16°FOct 22Oct 28Nov 1Nov 3Nov 5Nov 9Nov 12Nov 16Nov 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°F148142137133130126122117111
32°F165159154150146143139135128
28°F184178173169165161157151145
24°F204198193188184179175169162
20°F224216211208202198193187180
16°F244236231227221216211205197

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
7,683
Cooling degree days, base 65°F
752
Growing degree days, base 40°F
4,745
Growing degree days, base 45°F
3,714
Growing degree days, base 50°F
2,793
Growing degree days, base 55°F
1,988
Growing degree days, base 60°F
1,305

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,51900
February1,24601
March996013
April580267
May25233276
June45145551
July8276733
August18214660
September15077388
October537597
November95909
December1,37600

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 4 km from Huron. 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 USW00014936 (Huron Rgnl AP). Public domain.