Stanfield climate

Stanfield Frost Dates and Growing Season

NOAA 1991-2020 normals for Casa Grande, 23.1 km from Stanfield, elevation 1400 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Casa Grande. 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 5 and the first fall freeze around December 6, a growing season of about 305 days.

Median at 36°F
last February 26, first November 24
Median at 32°F
last February 5, first December 6
Median at 28°F
last January 14, 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°FMar 16Mar 9Mar 4Mar 1Feb 26Feb 21Feb 16Feb 9Jan 31
32°FFeb 28Feb 23Feb 17Feb 10Feb 5Jan 31Jan 26Jan 16Jan 5
28°FFeb 15Feb 6Jan 31Jan 23Jan 14Jan 8Jan 1Dec 28Dec 16
24°FFeb 5Jan 23Jan 16Jan 11Jan 6Jan 1Dec 30Dec 19Dec 10
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 13Nov 17Nov 21Nov 24Nov 27Dec 1Dec 5Dec 11
32°FNov 18Nov 24Nov 29Dec 3Dec 6Dec 10Dec 15Dec 21Dec 29
28°FNov 29Dec 6Dec 10Dec 15Dec 22Dec 27Jan 1Jan 8Jan 24
24°FDec 9Dec 15Dec 23Dec 29Jan 1Jan 6Jan 10Jan 17Jan 31
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°F299289283277271265260253243
32°F340329320313305298291284273
28°F365362354347340333326317304
24°F365365365365365365365353340
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
79% of years
24°F or colder
28% of years
20°F or colder
3% 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
1,241
Cooling degree days, base 65°F
3,963
Growing degree days, base 40°F
11,848
Growing degree days, base 45°F
10,032
Growing degree days, base 50°F
8,266
Growing degree days, base 55°F
6,633
Growing degree days, base 60°F
5,199

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January3451145
February2296205
March10560421
April23181608
May2418881
June06851,135
July08511,316
August08151,280
September06171,066
October12285738
November15143349
December3721123

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 23.1 km from Stanfield. 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 USC00021306 (Casa Grande). Public domain.