Tea climate

Tea Frost Dates and Growing Season

NOAA 1991-2020 normals for Sioux Falls, 18 km from Tea, elevation 1430 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Sioux Falls. 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 1 and the first fall freeze around October 6, a growing season of about 157 days.

Median at 36°F
last May 10, first September 27
Median at 32°F
last May 1, first October 6
Median at 28°F
last April 22, first October 17

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 23May 18May 15May 12May 10May 7May 5May 2Apr 29
32°FMay 14May 10May 6May 3May 1Apr 29Apr 26Apr 23Apr 18
28°FMay 5May 1Apr 28Apr 25Apr 22Apr 19Apr 16Apr 12Apr 8
24°FApr 27Apr 22Apr 19Apr 16Apr 13Apr 10Apr 7Apr 3Mar 30
20°FApr 19Apr 13Apr 10Apr 7Apr 4Apr 1Mar 28Mar 23Mar 18
16°FApr 10Apr 5Apr 1Mar 29Mar 25Mar 21Mar 17Mar 13Mar 9

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 14Sep 19Sep 22Sep 25Sep 27Sep 30Oct 2Oct 5Oct 10
32°FSep 23Sep 27Sep 30Oct 3Oct 6Oct 9Oct 12Oct 15Oct 20
28°FOct 1Oct 6Oct 11Oct 14Oct 17Oct 20Oct 22Oct 25Oct 30
24°FOct 13Oct 19Oct 22Oct 24Oct 27Oct 29Nov 1Nov 4Nov 10
20°FOct 23Oct 27Oct 30Nov 1Nov 4Nov 6Nov 9Nov 12Nov 17
16°FOct 30Nov 2Nov 6Nov 9Nov 11Nov 13Nov 17Nov 21Nov 25

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°F156150146142139135131127121
32°F176170165161157153148144138
28°F196190184180176173168162154
24°F217210205200197193188183176
20°F235228222217214210206201194
16°F252245240234231226222217210

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
7,249
Cooling degree days, base 65°F
847
Growing degree days, base 40°F
5,008
Growing degree days, base 45°F
3,941
Growing degree days, base 50°F
2,989
Growing degree days, base 55°F
2,150
Growing degree days, base 60°F
1,436

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,46100
February1,19501
March942117
April538585
May22745305
June33178596
July5294755
August12227680
September12689419
October4858120
November908012
December1,31700

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 18 km from Tea. 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 USW00014944 (Sioux Falls). Public domain.