Goodhue County climate

Goodhue County Frost Dates and Growing Season

NOAA 1991-2020 normals for Zumbrota, 13.1 km from Goodhue County, elevation 970 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Zumbrota. 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 9 and the first fall freeze around September 30, a growing season of about 144 days.

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

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 9Sep 13Sep 16Sep 19Sep 21Sep 24Sep 27Oct 1Oct 4
32°FSep 17Sep 22Sep 25Sep 28Sep 30Oct 2Oct 4Oct 7Oct 11
28°FSep 26Sep 30Oct 2Oct 5Oct 8Oct 10Oct 14Oct 17Oct 22
24°FOct 4Oct 9Oct 13Oct 17Oct 20Oct 22Oct 25Oct 29Nov 2
20°FOct 15Oct 20Oct 24Oct 28Oct 30Nov 1Nov 4Nov 8Nov 13
16°FOct 26Oct 31Nov 2Nov 4Nov 7Nov 11Nov 14Nov 18Nov 24

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°F145140135131127124120114108
32°F163156152148144141136133127
28°F183177172168164160155151144
24°F208201196191187182177172166
20°F226219214210207203199193185
16°F243237231227223219215211203

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
8,127
Cooling degree days, base 65°F
507
Growing degree days, base 40°F
4,301
Growing degree days, base 45°F
3,303
Growing degree days, base 50°F
2,419
Growing degree days, base 55°F
1,651
Growing degree days, base 60°F
1,008

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,60000
February1,33600
March1,07009
April620256
May29426234
June60114504
July15187637
August33127559
September18545325
October552587
November96907
December1,39500

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 13.1 km from Goodhue County. 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 USC00219249 (Zumbrota). Public domain.