Weimar climate

Weimar Frost Dates and Growing Season

NOAA 1991-2020 normals for Columbus, 20 km from Weimar, elevation 225 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Columbus. 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 9 and the first fall freeze around November 20, a growing season of about 255 days.

Median at 36°F
last March 23, first November 9
Median at 32°F
last March 9, first November 20
Median at 28°F
last February 25, first December 3

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 13Apr 5Mar 31Mar 27Mar 23Mar 18Mar 13Mar 6Feb 28
32°FMar 31Mar 23Mar 18Mar 13Mar 9Mar 4Feb 28Feb 23Feb 13
28°FMar 19Mar 12Mar 6Feb 28Feb 25Feb 20Feb 13Feb 1Jan 22
24°FMar 9Mar 1Feb 24Feb 17Feb 7Jan 31Jan 24Jan 13Dec 30
20°FMar 1Feb 17Feb 4Jan 28Jan 20Jan 13Jan 5Dec 30Dec 15
16°FFeb 23Feb 6Jan 29Jan 18Jan 11Jan 5Jan 1Dec 26Dec 13

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 21Oct 29Nov 2Nov 5Nov 9Nov 13Nov 18Nov 25Dec 2
32°FNov 1Nov 5Nov 10Nov 15Nov 20Nov 26Dec 1Dec 5Dec 13
28°FNov 6Nov 14Nov 22Nov 28Dec 3Dec 8Dec 16Dec 27Jan 4
24°FNov 17Nov 27Dec 3Dec 9Dec 20Dec 30Jan 4Jan 10Feb 1
20°FNov 28Dec 7Dec 16Dec 25Jan 1Jan 5Jan 11Jan 20Feb 7
16°FDec 6Dec 17Dec 26Dec 31Jan 4Jan 10Jan 17Jan 28Feb 6

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°F265252244238231225219213203
32°F291278270261255248241233223
28°F328313302293284276267258247
24°F365349337330320311303292276
20°F365365365363352342333321304
16°F365365365365365365365357340

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
99% of years
24°F or colder
90% of years
20°F or colder
64% of years
16°F or colder
27% 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
1,556
Cooling degree days, base 65°F
2,984
Growing degree days, base 40°F
10,590
Growing degree days, base 45°F
8,836
Growing degree days, base 50°F
7,171
Growing degree days, base 55°F
5,627
Growing degree days, base 60°F
4,225

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January43411141
February28724207
March16169390
April49146549
May4341801
June0494943
July05741,039
August05971,062
September2431879
October42216640
November19762340
December38021181

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 20 km from Weimar. 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 USC00411911 (Columbus). Public domain.