Culloden climate

Culloden Frost Dates and Growing Season

NOAA 1991-2020 normals for Hamlin, 16.4 km from Culloden, elevation 680 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Hamlin. 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 23 and the first fall freeze around October 21, a growing season of about 180 days.

Median at 36°F
last May 2, first October 12
Median at 32°F
last April 23, first October 21
Median at 28°F
last April 9, first October 30

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 20May 14May 10May 6May 2Apr 30Apr 27Apr 23Apr 19
32°FMay 9May 4Apr 30Apr 26Apr 23Apr 20Apr 17Apr 13Apr 8
28°FApr 27Apr 20Apr 17Apr 13Apr 9Apr 6Apr 3Mar 31Mar 24
24°FApr 13Apr 6Apr 4Apr 1Mar 29Mar 26Mar 21Mar 17Mar 11
20°FApr 3Mar 29Mar 24Mar 20Mar 17Mar 13Mar 8Mar 3Feb 25
16°FMar 22Mar 16Mar 12Mar 6Mar 3Feb 28Feb 23Feb 14Feb 5

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 1Oct 5Oct 7Oct 10Oct 12Oct 15Oct 17Oct 20Oct 24
32°FOct 9Oct 13Oct 16Oct 18Oct 21Oct 23Oct 26Oct 29Nov 2
28°FOct 17Oct 21Oct 24Oct 27Oct 30Nov 1Nov 3Nov 6Nov 11
24°FOct 26Oct 31Nov 3Nov 5Nov 8Nov 11Nov 14Nov 19Nov 25
20°FNov 5Nov 9Nov 14Nov 18Nov 22Nov 26Nov 30Dec 4Dec 11
16°FNov 15Nov 23Nov 28Dec 1Dec 6Dec 12Dec 18Dec 23Dec 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°F180175170166163159155149142
32°F199193188183180176171166159
28°F224215210205201198193188180
24°F247240235230225221216211203
20°F278268262256251247241234226
16°F310300293286279273266258250

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
4,559
Cooling degree days, base 65°F
1,196
Growing degree days, base 40°F
6,458
Growing degree days, base 45°F
5,106
Growing degree days, base 50°F
3,907
Growing degree days, base 55°F
2,858
Growing degree days, base 60°F
1,957

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January96909
February784011
March630366
April31117210
May10695457
June12231669
July0344809
August1320784
September41161570
October27522246
November585159
December845017

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 16.4 km from Culloden. 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 USC00463846 (Hamlin). Public domain.