Sky Valley Frost Dates and Growing Season

NOAA 1991-2020 normals for Palm Springs, 16.1 km from Sky Valley, elevation 425 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Palm Springs. A median date has an even chance of a later freeze in spring, or an earlier one in fall.

A freeze (32°F or colder) happens in only 21 percent of years at Palm Springs, so there is no typical freeze season.

Median at 36°F: last January 10, first December 22
Median at 32°F: last January 1, first December 31

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.

Threshold	10%	20%	30%	40%	50%	60%	70%	80%	90%
36°F	Feb 18	Feb 3	Jan 25	Jan 16	Jan 10	Jan 4	Dec 31	Dec 24	Dec 14
32°F	Jan 18	Jan 10	Jan 7	Jan 3	Jan 1	Dec 30	Dec 26	Dec 20	Dec 12
28°F	–	–	–	–	–	–	–	–	–
24°F	–	–	–	–	–	–	–	–	–
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.

Threshold	10%	20%	30%	40%	50%	60%	70%	80%	90%
36°F	Dec 5	Dec 9	Dec 14	Dec 17	Dec 22	Dec 27	Jan 1	Jan 8	Jan 25
32°F	Dec 11	Dec 17	Dec 21	Dec 27	Dec 31	Jan 2	Jan 5	Jan 10	Jan 16
28°F	–	–	–	–	–	–	–	–	–
24°F	–	–	–	–	–	–	–	–	–
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.

Threshold	10%	20%	30%	40%	50%	60%	70%	80%	90%
36°F	365	365	363	357	351	345	337	326	312
32°F	365	365	365	365	365	365	365	365	358
28°F	365	365	365	365	365	365	365	365	365
24°F	365	365	365	365	365	365	365	365	365
20°F	365	365	365	365	365	365	365	365	365
16°F	365	365	365	365	365	365	365	365	365

How often it gets that cold

The share of years with at least one night at or below each temperature.

36°F or colder: 76% of years
32°F or colder: 21% of years
28°F or colder: 1% of years
24°F or colder: 0% of years
20°F or colder: 0% 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: 733
Cooling degree days, base 65°F: 4,462
Growing degree days, base 40°F: 12,855
Growing degree days, base 45°F: 11,031
Growing degree days, base 50°F: 9,215
Growing degree days, base 55°F: 7,460
Growing degree days, base 60°F: 5,859

Growing degree days by month, base 50°F

Heating and cooling by month

Month	Heating DD	Cooling DD	Growing DD 50
January	203	14	280
February	133	28	315
March	57	117	526
April	11	256	695
May	1	453	916
June	0	675	1,125
July	0	873	1,338
August	0	873	1,338
September	0	680	1,130
October	3	389	851
November	71	102	482
December	254	5	221

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 16.1 km from Sky Valley. Low ground, valleys and open fields freeze earlier and later than a town center or a hillside.

Sources

NOAA NCEI U.S. Climate Normals, 1991-2020, annual and seasonal normals for station USC00046635 (Palm Springs). Public domain.