Clifton climate

Clifton Frost Dates and Growing Season

NOAA 1991-2020 normals for Clay Ctr, 25.1 km from Clifton, elevation 1201 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Clay Ctr. 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 19 and the first fall freeze around October 19, a growing season of about 181 days.

Median at 36°F
last April 29, first October 10
Median at 32°F
last April 19, first October 19
Median at 28°F
last April 9, first October 28

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 11May 6May 3May 1Apr 29Apr 26Apr 23Apr 19Apr 14
32°FMay 2Apr 28Apr 25Apr 21Apr 19Apr 16Apr 13Apr 8Apr 4
28°FApr 23Apr 20Apr 16Apr 13Apr 9Apr 6Apr 3Mar 31Mar 23
24°FApr 15Apr 9Apr 5Apr 2Mar 31Mar 28Mar 24Mar 19Mar 12
20°FApr 5Apr 1Mar 29Mar 24Mar 20Mar 16Mar 13Mar 9Mar 2
16°FMar 30Mar 22Mar 17Mar 13Mar 10Mar 6Mar 2Feb 27Feb 21

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

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°F181175171167164160155150144
32°F202195189185181178173168160
28°F222215210206202198193188181
24°F243235230225220215211206200
20°F263256250245240235229223215
16°F288277271265260255250242231

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
5,317
Cooling degree days, base 65°F
1,467
Growing degree days, base 40°F
6,432
Growing degree days, base 45°F
5,185
Growing degree days, base 50°F
4,067
Growing degree days, base 55°F
3,074
Growing degree days, base 60°F
2,207

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,13901
February91008
March683260
April36215181
May118104457
June8303745
July1458922
August3381843
September60175567
October31028240
November686141
December1,03802

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 25.1 km from Clifton. Low ground, valleys and open fields freeze earlier and later than a town center or a hillside.

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Sources

NOAA NCEI U.S. Climate Normals, 1991-2020, annual and seasonal normals for station USC00141559 (Clay Ctr). Public domain.