Pierre climate

Pierre Frost Dates and Growing Season

NOAA 1991-2020 normals for Pierre Rgnl AP, 5.4 km from Pierre, elevation 1742 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Pierre 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 3, a growing season of about 148 days.

Median at 36°F
last May 16, first September 25
Median at 32°F
last May 6, first October 3
Median at 28°F
last April 26, first October 12

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 30May 25May 22May 19May 16May 13May 11May 7May 3
32°FMay 21May 16May 12May 9May 6May 4May 2Apr 29Apr 24
28°FMay 10May 5May 1Apr 29Apr 26Apr 23Apr 20Apr 17Apr 12
24°FMay 1Apr 26Apr 22Apr 19Apr 17Apr 14Apr 10Apr 6Apr 1
20°FApr 22Apr 17Apr 13Apr 9Apr 6Apr 3Apr 1Mar 28Mar 20
16°FApr 13Apr 8Apr 4Apr 1Mar 29Mar 26Mar 20Mar 15Mar 10

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 17Sep 20Sep 23Sep 25Sep 28Oct 1Oct 3Oct 8
32°FSep 20Sep 24Sep 28Sep 30Oct 3Oct 6Oct 9Oct 13Oct 17
28°FSep 27Oct 1Oct 5Oct 9Oct 12Oct 15Oct 19Oct 22Oct 27
24°FOct 5Oct 12Oct 16Oct 19Oct 23Oct 26Oct 29Nov 1Nov 5
20°FOct 16Oct 22Oct 27Oct 29Nov 1Nov 4Nov 6Nov 10Nov 14
16°FOct 27Nov 1Nov 3Nov 6Nov 9Nov 12Nov 15Nov 19Nov 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°F149144139135131128124119114
32°F167160156152148145141136130
28°F189181175171167163158153146
24°F208201196191187182177171164
20°F228220214209205201196191182
16°F247239233229223219214209201

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
7,348
Cooling degree days, base 65°F
837
Growing degree days, base 40°F
4,878
Growing degree days, base 45°F
3,820
Growing degree days, base 50°F
2,889
Growing degree days, base 55°F
2,080
Growing degree days, base 60°F
1,394

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,42100
February1,17201
March952013
April575267
May26927257
June50134535
July6314773
August15262713
September13491416
October5196106
November92908
December1,30800

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 5.4 km from Pierre. 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 USW00024025 (Pierre Rgnl AP). Public domain.