Britton climate

Britton Frost Dates and Growing Season

NOAA 1991-2020 normals for Tecumseh, 8.7 km from Britton, elevation 780 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Tecumseh. 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 3 and the first fall freeze around October 13, a growing season of about 160 days.

Median at 36°F
last May 14, first October 1
Median at 32°F
last May 3, first October 13
Median at 28°F
last April 23, first October 25

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 29May 24May 20May 17May 14May 11May 8May 4Apr 30
32°FMay 18May 12May 9May 6May 3Apr 30Apr 28Apr 25Apr 20
28°FMay 7May 3Apr 30Apr 26Apr 23Apr 20Apr 17Apr 14Apr 9
24°FApr 28Apr 22Apr 18Apr 15Apr 12Apr 8Apr 5Apr 3Mar 29
20°FApr 15Apr 8Apr 4Apr 2Mar 31Mar 29Mar 25Mar 21Mar 15
16°FApr 3Mar 31Mar 28Mar 24Mar 20Mar 17Mar 14Mar 10Mar 4

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 20Sep 23Sep 27Sep 30Oct 1Oct 4Oct 7Oct 10Oct 13
32°FSep 30Oct 4Oct 7Oct 10Oct 13Oct 16Oct 19Oct 22Oct 25
28°FOct 10Oct 16Oct 20Oct 23Oct 25Oct 28Oct 31Nov 2Nov 6
24°FOct 24Oct 30Nov 1Nov 3Nov 5Nov 8Nov 12Nov 16Nov 21
20°FNov 4Nov 7Nov 11Nov 14Nov 17Nov 20Nov 23Nov 27Dec 2
16°FNov 12Nov 18Nov 22Nov 26Nov 29Dec 1Dec 5Dec 11Dec 18

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°F158152148143140136132127119
32°F180173169164160157153148141
28°F203197193188184180176171163
24°F229222217213209205201196190
20°F255247241237232228224218212
16°F280270264259254249244238230

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
6,580
Cooling degree days, base 65°F
631
Growing degree days, base 40°F
4,792
Growing degree days, base 45°F
3,694
Growing degree days, base 50°F
2,734
Growing degree days, base 55°F
1,902
Growing degree days, base 60°F
1,195

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,27900
February1,08400
March919012
April550267
May24428271
June42135543
July6231690
August15168618
September11960394
October4396125
November788013
December1,09702

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 8.7 km from Britton. 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 USC00208080 (Tecumseh). Public domain.