Heber-Overgaard climate

Heber-Overgaard Frost Dates and Growing Season

NOAA 1991-2020 normals for Heber (black Mesa) RS, 2.6 km from Heber-Overgaard, elevation 6590 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Heber (black Mesa) RS. 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 23 and the first fall freeze around October 5, a growing season of about 135 days.

Median at 36°F
last June 3, first September 27
Median at 32°F
last May 23, first October 5
Median at 28°F
last May 8, first October 16

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°FJun 18Jun 12Jun 8Jun 5Jun 3May 31May 30May 26May 22
32°FJun 6Jun 2May 30May 27May 23May 20May 16May 11May 6
28°FMay 28May 21May 16May 12May 8May 5May 1Apr 28Apr 23
24°FMay 11May 5May 1Apr 27Apr 23Apr 19Apr 15Apr 9Apr 3
20°FApr 24Apr 18Apr 12Apr 8Apr 3Mar 30Mar 25Mar 18Mar 11
16°FApr 9Mar 30Mar 21Mar 14Mar 10Mar 6Mar 3Feb 27Feb 19

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 16Sep 19Sep 22Sep 25Sep 27Sep 30Oct 2Oct 4Oct 9
32°FSep 24Sep 28Oct 1Oct 3Oct 5Oct 8Oct 11Oct 15Oct 19
28°FOct 1Oct 5Oct 9Oct 13Oct 16Oct 19Oct 22Oct 26Nov 1
24°FOct 11Oct 17Oct 20Oct 24Oct 27Oct 30Nov 2Nov 5Nov 10
20°FOct 22Oct 29Nov 1Nov 4Nov 7Nov 11Nov 14Nov 18Nov 23
16°FNov 4Nov 9Nov 13Nov 17Nov 20Nov 22Nov 26Nov 29Dec 3

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°F13412812311911511110810396
32°F155149144139135131126121114
28°F182175170164159155150145136
24°F210202196192187182177171162
20°F244235228222217212206199189
16°F278270262257252246240233223

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
5,704
Cooling degree days, base 65°F
331
Growing degree days, base 40°F
4,532
Growing degree days, base 45°F
3,311
Growing degree days, base 50°F
2,298
Growing degree days, base 55°F
1,467
Growing degree days, base 60°F
814

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,00000
February80501
March71009
April516043
May3165182
June7367444
July5141601
August1597547
September12621348
October4190108
November720014
December1,00001

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 2.6 km from Heber-Overgaard. 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 USC00023961 (Heber (black Mesa) RS). Public domain.