Merkel climate

Merkel Frost Dates and Growing Season

NOAA 1991-2020 normals for Merkel 12 Sw, 19.7 km from Merkel, elevation 2249 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Merkel 12 Sw. 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 April 2 and the first fall freeze around November 3, a growing season of about 215 days.

Median at 36°F
last April 14, first October 27
Median at 32°F
last April 2, first November 3
Median at 28°F
last March 20, first November 14

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 28Apr 23Apr 20Apr 17Apr 14Apr 10Apr 7Apr 2Mar 29
32°FApr 20Apr 14Apr 9Apr 5Apr 2Mar 30Mar 25Mar 21Mar 15
28°FApr 9Apr 3Mar 30Mar 24Mar 20Mar 16Mar 12Mar 8Mar 1
24°FMar 30Mar 21Mar 16Mar 12Mar 9Mar 5Mar 2Feb 25Feb 19
20°FMar 16Mar 10Mar 6Mar 2Feb 27Feb 22Feb 16Feb 7Jan 27
16°FMar 8Mar 1Feb 24Feb 17Feb 10Feb 1Jan 25Jan 16Jan 2

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 14Oct 18Oct 21Oct 24Oct 27Oct 29Nov 1Nov 3Nov 8
32°FOct 21Oct 27Oct 30Nov 1Nov 3Nov 6Nov 9Nov 12Nov 18
28°FOct 30Nov 4Nov 7Nov 10Nov 14Nov 17Nov 21Nov 26Dec 1
24°FNov 7Nov 13Nov 18Nov 21Nov 25Nov 29Dec 2Dec 5Dec 11
20°FNov 18Nov 24Nov 29Dec 3Dec 6Dec 11Dec 16Dec 22Jan 1
16°FNov 30Dec 5Dec 11Dec 17Dec 21Dec 28Jan 5Jan 14Jan 31

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°F217210204199195191186181174
32°F240231224219215211205199192
28°F262254247243238232227219210
24°F286277270264259254249242233
20°F320306299292286279273265256
16°F357343333325317307300291278

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
93% 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
2,785
Cooling degree days, base 65°F
2,209
Growing degree days, base 40°F
8,783
Growing degree days, base 45°F
7,179
Growing degree days, base 50°F
5,707
Growing degree days, base 55°F
4,377
Growing degree days, base 60°F
3,213

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January667149
February508588
March32415220
April13578405
May33247679
June0423873
July0530995
August0502967
September13293731
October120104462
November36611175
December620163

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 19.7 km from Merkel. 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 USC00415852 (Merkel 12 Sw). Public domain.