Killian climate

Killian Frost Dates and Growing Season

NOAA 1991-2020 normals for Hammond 5 E, 25.6 km from Killian, elevation 35 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Hammond 5 E. 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 March 8 and the first fall freeze around November 19, a growing season of about 257 days.

Median at 36°F
last March 25, first November 6
Median at 32°F
last March 8, first November 19
Median at 28°F
last February 21, first December 2

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°FApr 16Apr 8Apr 3Mar 31Mar 25Mar 20Mar 15Mar 10Mar 1
32°FMar 31Mar 23Mar 18Mar 13Mar 8Mar 3Feb 27Feb 21Feb 12
28°FMar 17Mar 10Mar 3Feb 26Feb 21Feb 14Feb 7Jan 31Jan 20
24°FMar 6Feb 26Feb 14Feb 6Feb 1Jan 27Jan 20Jan 11Dec 30
20°FFeb 20Feb 5Jan 31Jan 25Jan 19Jan 14Jan 9Jan 3Dec 28
16°FJan 31Jan 28Jan 23Jan 20Jan 14Jan 10Jan 7Jan 5Jan 1

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°FOct 23Oct 29Nov 1Nov 4Nov 6Nov 9Nov 13Nov 18Nov 26
32°FNov 3Nov 7Nov 11Nov 15Nov 19Nov 23Nov 28Dec 1Dec 8
28°FNov 14Nov 20Nov 26Nov 30Dec 2Dec 8Dec 16Dec 25Jan 3
24°FNov 28Dec 5Dec 13Dec 23Dec 29Jan 2Jan 7Jan 15Jan 31
20°FDec 15Dec 28Jan 1Jan 3Jan 8Jan 13Jan 18Jan 26Feb 6
16°FDec 31Jan 2Jan 4Jan 7Jan 9Jan 13Jan 19Jan 22Jan 28

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°F259249242235230225219214205
32°F289278271264257251246237227
28°F328314304296288281274266256
24°F365351342334329320311303290
20°F365365365365363354345334324
16°F365365365365365365365365352

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
88% of years
20°F or colder
53% of years
16°F or colder
18% 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
1,797
Cooling degree days, base 65°F
2,467
Growing degree days, base 40°F
9,836
Growing degree days, base 45°F
8,096
Growing degree days, base 50°F
6,460
Growing degree days, base 55°F
4,966
Growing degree days, base 60°F
3,631

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January4746118
February33211157
March19441328
April73107486
May9272728
June0434883
July0511976
August0508973
September2378826
October60156563
November24231267
December41212154

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 25.6 km from Killian. 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 USC00164030 (Hammond 5 E). Public domain.