Death Valley Frost Dates and Growing Season

NOAA 1991-2020 normals for Death Valley Np, 25.2 km from Death Valley, elevation -194 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Death Valley Np. 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 January 1 and the first fall freeze around December 19, a growing season of about 350 days.

Median at 36°F: last January 21, first December 7
Median at 32°F: last January 1, first December 19
Median at 28°F: last December 27, first December 25

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 11	Feb 3	Jan 31	Jan 26	Jan 21	Jan 17	Jan 12	Jan 6	Dec 31
32°F	Jan 21	Jan 13	Jan 9	Jan 5	Jan 1	Dec 30	Dec 26	Dec 21	Dec 14
28°F	Jan 11	Jan 5	Dec 31	Dec 30	Dec 27	Dec 25	Dec 22	Dec 19	Dec 13
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	Nov 23	Nov 28	Dec 2	Dec 4	Dec 7	Dec 10	Dec 13	Dec 17	Dec 22
32°F	Dec 4	Dec 8	Dec 12	Dec 16	Dec 19	Dec 21	Dec 24	Dec 28	Jan 4
28°F	Dec 12	Dec 17	Dec 20	Dec 23	Dec 25	Dec 27	Dec 30	Jan 1	Jan 8
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	344	337	331	326	321	315	310	304	295
32°F	365	362	358	354	350	347	342	336	329
28°F	365	365	365	365	365	365	365	361	352
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: 100% of years
32°F or colder: 81% of years
28°F or colder: 24% of years
24°F or colder: 1% 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: 954
Cooling degree days, base 65°F: 6,020
Growing degree days, base 40°F: 14,191
Growing degree days, base 45°F: 12,370
Growing degree days, base 50°F: 10,583
Growing degree days, base 55°F: 8,904
Growing degree days, base 60°F: 7,382

Growing degree days by month, base 50°F

Heating and cooling by month

Month	Heating DD	Cooling DD	Growing DD 50
January	317	2	167
February	133	31	319
March	31	181	615
April	5	392	837
May	0	709	1,173
June	0	977	1,427
July	0	1,215	1,680
August	0	1,156	1,621
September	0	852	1,302
October	3	433	894
November	103	71	420
December	363	2	128

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 25.2 km from Death 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 USC00042319 (Death Valley Np). Public domain.