Coolidge climate

Coolidge Frost Dates and Growing Season

NOAA 1991-2020 normals for Casa Grande Nm, 2.5 km from Coolidge, elevation 1419 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Casa Grande Nm. 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 17 and the first fall freeze around November 29, a growing season of about 284 days.

Median at 36°F
last March 8, first November 19
Median at 32°F
last February 17, first November 29
Median at 28°F
last January 26, first December 12

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 5Mar 27Mar 19Mar 13Mar 8Mar 4Mar 1Feb 25Feb 16
32°FMar 8Mar 3Feb 28Feb 22Feb 17Feb 11Feb 6Jan 31Jan 22
28°FFeb 23Feb 15Feb 6Feb 2Jan 26Jan 19Jan 11Jan 3Dec 26
24°FFeb 4Jan 27Jan 18Jan 11Jan 7Jan 3Dec 31Dec 23Dec 13
20°FJan 27Jan 19Jan 11Jan 8Jan 5Jan 2Jan 1Dec 31Dec 22
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 4Nov 9Nov 13Nov 16Nov 19Nov 21Nov 24Nov 29Dec 3
32°FNov 12Nov 19Nov 22Nov 25Nov 29Dec 2Dec 5Dec 10Dec 15
28°FNov 23Nov 29Dec 4Dec 8Dec 12Dec 15Dec 21Dec 27Jan 6
24°FDec 2Dec 10Dec 16Dec 23Dec 28Jan 1Jan 5Jan 13Jan 24
20°FDec 19Dec 28Jan 1Jan 1Jan 4Jan 7Jan 9Jan 19Jan 27
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°F277269262257251246240233222
32°F314303295289284278272266257
28°F355345337329322316308299288
24°F365365365365363356348339329
20°F365365365365365365365365363
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
100% of years
28°F or colder
95% of years
24°F or colder
57% of years
20°F or colder
15% of years
16°F or colder
3% 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
1,452
Cooling degree days, base 65°F
3,778
Growing degree days, base 40°F
11,455
Growing degree days, base 45°F
9,653
Growing degree days, base 50°F
7,927
Growing degree days, base 55°F
6,349
Growing degree days, base 60°F
4,970

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January3941113
February2693173
March14341366
April41149558
May4382843
June06471,096
July08321,297
August07981,263
September06071,057
October18278726
November16740331
December4160103

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 2.5 km from Coolidge. 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 USC00021314 (Casa Grande Nm). Public domain.