Peridot climate

Peridot Frost Dates and Growing Season

NOAA 1991-2020 normals for San Carlos Reservoir, 15.7 km from Peridot, elevation 2532 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for San Carlos Reservoir. 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 March 13 and the first fall freeze around November 19, a growing season of about 247 days.

Median at 36°F
last April 1, first November 9
Median at 32°F
last March 13, first November 19
Median at 28°F
last February 17, first December 1

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 21Apr 14Apr 9Apr 5Apr 1Mar 29Mar 25Mar 19Mar 11
32°FApr 6Mar 30Mar 24Mar 19Mar 13Mar 8Mar 3Feb 26Feb 17
28°FMar 13Mar 5Feb 28Feb 24Feb 17Feb 11Feb 5Jan 30Jan 21
24°FFeb 25Feb 15Feb 6Jan 31Jan 25Jan 19Jan 11Jan 3Dec 24
20°FFeb 16Feb 3Jan 26Jan 17Jan 9Jan 3Dec 29Dec 20Dec 12
16°FFeb 6Jan 31Jan 28Jan 23Jan 18Jan 14Jan 8Jan 2Dec 30

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°FOct 24Oct 31Nov 3Nov 6Nov 9Nov 12Nov 15Nov 18Nov 23
32°FNov 3Nov 9Nov 13Nov 17Nov 19Nov 22Nov 26Nov 30Dec 4
28°FNov 14Nov 20Nov 25Nov 29Dec 1Dec 4Dec 8Dec 12Dec 18
24°FNov 25Dec 1Dec 5Dec 9Dec 13Dec 18Dec 23Jan 1Jan 14
20°FDec 5Dec 12Dec 19Dec 24Dec 31Jan 5Jan 13Jan 24Feb 4
16°FDec 30Jan 1Jan 5Jan 10Jan 16Jan 22Jan 26Jan 30Feb 2

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°F244235229224219214209203197
32°F276268260253247241235229219
28°F317308298291284278271262249
24°F360348340334326318310301289
20°F365365365365365356347336324
16°F365365365365365365365365356

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
93% of years
20°F or colder
49% of years
16°F or colder
13% 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
2,566
Cooling degree days, base 65°F
2,479
Growing degree days, base 40°F
9,089
Growing degree days, base 45°F
7,400
Growing degree days, base 50°F
5,890
Growing degree days, base 55°F
4,586
Growing degree days, base 60°F
3,454

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January614013
February444056
March3213183
April12751380
May21237681
June1493942
July06111,076
August05751,040
September5387833
October68120519
November3443153
December623017

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 15.7 km from Peridot. 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 USC00027480 (San Carlos Reservoir). Public domain.