Greenleaf climate

Greenleaf Frost Dates and Growing Season

NOAA 1991-2020 normals for Homedale 1 Se, 11.1 km from Greenleaf, elevation 2230 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Homedale 1 Se. 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 April 24 and the first fall freeze around October 9, a growing season of about 169 days.

Median at 36°F
last May 5, first September 28
Median at 32°F
last April 24, first October 9
Median at 28°F
last April 10, first October 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°FMay 24May 15May 11May 7May 5May 2Apr 30Apr 28Apr 22
32°FMay 5May 1Apr 29Apr 26Apr 24Apr 21Apr 18Apr 14Apr 9
28°FApr 25Apr 20Apr 17Apr 13Apr 10Apr 6Apr 3Mar 31Mar 25
24°FApr 13Apr 7Apr 3Mar 31Mar 26Mar 19Mar 15Mar 9Mar 1
20°FMar 30Mar 18Mar 11Mar 6Mar 1Feb 26Feb 23Feb 17Feb 10
16°FMar 4Feb 25Feb 19Feb 14Feb 8Feb 4Jan 30Jan 18Jan 7

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 20Sep 24Sep 26Sep 28Oct 1Oct 3Oct 6Oct 11
32°FSep 26Sep 30Oct 3Oct 6Oct 9Oct 12Oct 15Oct 18Oct 23
28°FOct 8Oct 12Oct 16Oct 18Oct 22Oct 24Oct 28Nov 1Nov 4
24°FOct 18Oct 24Oct 27Oct 30Nov 1Nov 4Nov 7Nov 12Nov 19
20°FOct 29Nov 1Nov 6Nov 10Nov 14Nov 19Nov 23Nov 28Dec 2
16°FNov 5Nov 12Nov 19Nov 23Nov 28Dec 1Dec 5Dec 12Dec 24

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°F162155151147143139134129120
32°F187180176172169164160155150
28°F217208202198194190186181174
24°F248239233228222216210203196
20°F285275268262254249242234225
16°F328315307299294286279271261

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
5,615
Cooling degree days, base 65°F
819
Growing degree days, base 40°F
5,220
Growing degree days, base 45°F
4,001
Growing degree days, base 50°F
2,961
Growing degree days, base 55°F
2,097
Growing degree days, base 60°F
1,382

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,07300
February80501
March643019
April435189
May19335316
June61122512
July5336797
August9265721
September11158399
October4452101
November78006
December1,05701

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 11.1 km from Greenleaf. 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 USC00104318 (Homedale 1 Se). Public domain.