Gregory climate

Gregory Frost Dates and Growing Season

NOAA 1991-2020 normals for Gregory, 0.5 km from Gregory, elevation 2160 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Gregory. 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 May 6 and the first fall freeze around October 3, a growing season of about 149 days.

Median at 36°F
last May 15, first September 26
Median at 32°F
last May 6, first October 3
Median at 28°F
last April 26, first October 13

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 29May 24May 21May 18May 15May 13May 10May 8May 4
32°FMay 20May 15May 11May 8May 6May 4May 1Apr 28Apr 23
28°FMay 9May 4May 1Apr 29Apr 26Apr 23Apr 20Apr 17Apr 12
24°FApr 30Apr 26Apr 22Apr 19Apr 17Apr 13Apr 10Apr 7Apr 3
20°FApr 22Apr 17Apr 13Apr 10Apr 7Apr 4Apr 1Mar 29Mar 22
16°FApr 13Apr 8Apr 4Apr 1Mar 30Mar 26Mar 22Mar 18Mar 12

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 14Sep 18Sep 22Sep 24Sep 26Sep 28Oct 1Oct 4Oct 8
32°FSep 21Sep 25Sep 29Oct 1Oct 3Oct 6Oct 9Oct 13Oct 17
28°FSep 29Oct 3Oct 6Oct 9Oct 13Oct 15Oct 18Oct 21Oct 25
24°FOct 6Oct 13Oct 17Oct 19Oct 22Oct 25Oct 28Nov 1Nov 5
20°FOct 18Oct 22Oct 26Oct 28Oct 31Nov 2Nov 5Nov 10Nov 14
16°FOct 27Oct 31Nov 2Nov 5Nov 9Nov 12Nov 14Nov 18Nov 23

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°F148143138135132129125120114
32°F168162157153149145141137131
28°F188181177172168163159155149
24°F208200195191188184180176168
20°F227220214210206202197193185
16°F247238233228222218214208201

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
7,208
Cooling degree days, base 65°F
779
Growing degree days, base 40°F
4,837
Growing degree days, base 45°F
3,773
Growing degree days, base 50°F
2,833
Growing degree days, base 55°F
2,024
Growing degree days, base 60°F
1,335

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,36900
February1,13402
March941016
April588267
May27928252
June53135533
July7290748
August17233682
September14084406
October5126112
November903014
December1,26600

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 0.5 km from Gregory. 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 USC00393452 (Gregory). Public domain.