Greeley Hill climate

Greeley Hill Frost Dates and Growing Season

NOAA 1991-2020 normals for Groveland 2, 13.9 km from Greeley Hill, elevation 2800 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Groveland 2. 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 22 and the first fall freeze around November 2, a growing season of about 192 days.

Median at 36°F
last May 11, first October 14
Median at 32°F
last April 22, first November 2
Median at 28°F
last March 29, first November 19

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 30May 25May 18May 14May 11May 8May 4Apr 30Apr 25
32°FMay 14May 7May 1Apr 27Apr 22Apr 18Apr 14Apr 9Apr 5
28°FApr 22Apr 13Apr 7Apr 2Mar 29Mar 25Mar 19Mar 13Mar 5
24°FMar 25Mar 15Mar 9Mar 3Feb 27Feb 21Feb 12Feb 4Jan 20
20°FMar 1Feb 21Feb 10Feb 3Jan 23Jan 14Jan 5Dec 31Dec 20
16°FFeb 7Jan 29Jan 18Jan 11Jan 5Jan 1Dec 29Dec 21Dec 11

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 27Oct 1Oct 6Oct 11Oct 14Oct 18Oct 22Oct 28Nov 2
32°FOct 13Oct 20Oct 26Oct 30Nov 2Nov 5Nov 8Nov 13Nov 20
28°FOct 30Nov 5Nov 9Nov 14Nov 19Nov 23Nov 26Dec 1Dec 7
24°FNov 15Nov 21Nov 26Dec 1Dec 4Dec 9Dec 14Dec 19Dec 29
20°FNov 29Dec 6Dec 14Dec 19Dec 25Dec 29Jan 3Jan 14Jan 31
16°FDec 7Dec 18Dec 25Dec 29Jan 2Jan 6Jan 12Jan 22Feb 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°F183173167161156151145139128
32°F220209203197192185179172163
28°F267255247241235229221213200
24°F327312302293285277269261250
20°F365362354345336328319306293
16°F365365365365365365365355341

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
85% of years
16°F or colder
35% 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
4,099
Cooling degree days, base 65°F
802
Growing degree days, base 40°F
5,994
Growing degree days, base 45°F
4,490
Growing degree days, base 50°F
3,242
Growing degree days, base 55°F
2,240
Growing degree days, base 60°F
1,434

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January70706
February602012
March544050
April4081110
May22325281
June55116512
July3274736
August3245707
September56124520
October24517253
November522052
December73304

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 13.9 km from Greeley Hill. 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 USC00043669 (Groveland 2). Public domain.