Apache Junction climate

Apache Junction Frost Dates and Growing Season

NOAA 1991-2020 normals for Apache Junction 5 Ne, 8.3 km from Apache Junction, elevation 2070 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Apache Junction 5 Ne. 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 February 11 and the first fall freeze around December 10, a growing season of about 304 days.

Median at 36°F
last March 6, first November 28
Median at 32°F
last February 11, first December 10
Median at 28°F
last January 13, first December 22

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 1Mar 24Mar 16Mar 10Mar 6Mar 1Feb 24Feb 17Feb 7
32°FMar 7Feb 28Feb 21Feb 16Feb 11Feb 5Jan 27Jan 18Jan 5
28°FFeb 18Feb 11Feb 3Jan 24Jan 13Jan 7Jan 1Dec 22Dec 12
24°FFeb 9Jan 28Jan 18Jan 9Jan 4Jan 1Dec 26Dec 16Dec 8
20°F–––––––––
16°F–––––––––

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°FNov 7Nov 15Nov 19Nov 23Nov 28Dec 1Dec 5Dec 10Dec 15
32°FNov 19Nov 26Dec 1Dec 6Dec 10Dec 14Dec 19Dec 25Jan 1
28°FNov 28Dec 4Dec 11Dec 16Dec 22Dec 31Jan 6Jan 16Feb 1
24°FDec 1Dec 10Dec 17Dec 26Jan 1Jan 6Jan 10Jan 22Feb 4
20°F–––––––––
16°F–––––––––

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°F302290280273266259252242229
32°F341330321314304296288280269
28°F365365362354344338330319307
24°F365365365365365365365355338
20°F365365365365365365365365365
16°F365365365365365365365365365

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
99% of years
28°F or colder
78% of years
24°F or colder
30% of years
20°F or colder
4% of years
16°F or colder
0% 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
1,216
Cooling degree days, base 65°F
3,768
Growing degree days, base 40°F
11,681
Growing degree days, base 45°F
9,871
Growing degree days, base 50°F
8,111
Growing degree days, base 55°F
6,470
Growing degree days, base 60°F
5,012

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January3192173
February2317211
March12947386
April40149560
May5374834
June06311,081
July08091,274
August07781,243
September06061,056
October15301752
November13263386
December3462155

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 8.3 km from Apache Junction. 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 USC00020288 (Apache Junction 5 Ne). Public domain.