Todd County climate

Todd County Frost Dates and Growing Season

NOAA 1991-2020 normals for Mission 14 S, 12.5 km from Todd County, elevation 2810 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Mission 14 S. 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 11 and the first fall freeze around October 2, a growing season of about 145 days.

Median at 36°F
last May 20, first September 25
Median at 32°F
last May 11, first October 2
Median at 28°F
last May 1, first October 13

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°FJun 1May 29May 25May 22May 20May 17May 15May 12May 8
32°FMay 25May 20May 16May 13May 11May 8May 5May 3Apr 30
28°FMay 15May 10May 6May 3May 1Apr 29Apr 26Apr 21Apr 16
24°FMay 3Apr 30Apr 27Apr 23Apr 20Apr 17Apr 13Apr 10Apr 6
20°FApr 25Apr 20Apr 17Apr 13Apr 10Apr 7Apr 4Apr 1Mar 25
16°FApr 18Apr 12Apr 8Apr 4Apr 1Mar 30Mar 25Mar 20Mar 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 13Sep 18Sep 21Sep 23Sep 25Sep 27Sep 29Oct 1Oct 6
32°FSep 21Sep 25Sep 28Sep 30Oct 2Oct 5Oct 8Oct 12Oct 16
28°FSep 28Oct 2Oct 6Oct 9Oct 13Oct 16Oct 18Oct 21Oct 25
24°FOct 5Oct 12Oct 16Oct 18Oct 21Oct 24Oct 26Oct 29Nov 3
20°FOct 15Oct 19Oct 23Oct 26Oct 29Nov 1Nov 3Nov 7Nov 13
16°FOct 22Oct 27Oct 31Nov 2Nov 5Nov 8Nov 12Nov 16Nov 21

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°F144138134131127123120115110
32°F163157153149145141137132125
28°F182176171167163159154149142
24°F202196191188183179175170162
20°F222215210205201197192188179
16°F242234229224218214209204195

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
7,314
Cooling degree days, base 65°F
689
Growing degree days, base 40°F
4,625
Growing degree days, base 45°F
3,572
Growing degree days, base 50°F
2,656
Growing degree days, base 55°F
1,871
Growing degree days, base 60°F
1,214

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,33000
February1,12002
March941016
April632153
May32720216
June73106485
July11262716
August22219662
September15976383
October5375106
November909017
December1,25401

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 12.5 km from Todd 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 USC00395638 (Mission 14 S). Public domain.