Dana Point Frost Dates and Growing Season

NOAA 1991-2020 normals for Laguna Beach, 11.6 km from Dana Point, elevation 44 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Laguna Beach. 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 20 percent of years at Laguna Beach, so there is no typical freeze season.

Median at 36°F: last January 30, first December 26
Median at 32°F: last January 6, first January 2

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 28	Feb 22	Feb 14	Feb 6	Jan 30	Jan 20	Jan 10	Jan 5	Dec 26
32°F	Feb 11	Jan 31	Jan 21	Jan 12	Jan 6	Jan 2	Dec 30	Dec 26	Dec 13
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 1	Dec 8	Dec 13	Dec 19	Dec 26	Dec 31	Jan 5	Jan 15	Feb 2
32°F	Dec 12	Dec 23	Dec 28	Dec 31	Jan 2	Jan 6	Jan 12	Jan 25	Feb 8
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	356	348	339	332	323	315	306	295
32°F	365	365	365	365	365	365	365	365	351
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: 89% of years
32°F or colder: 20% 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: 1,377
Cooling degree days, base 65°F: 682
Growing degree days, base 40°F: 8,431
Growing degree days, base 45°F: 6,606
Growing degree days, base 50°F: 4,786
Growing degree days, base 55°F: 3,062
Growing degree days, base 60°F: 1,666

Growing degree days by month, base 50°F

Heating and cooling by month

Month	Heating DD	Cooling DD	Growing DD 50
January	271	2	198
February	246	2	178
March	202	4	267
April	122	11	339
May	49	33	450
June	12	68	507
July	1	150	614
August	0	193	657
September	3	145	593
October	28	63	501
November	150	11	311
December	293	1	174

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 11.6 km from Dana Point. 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 USC00044647 (Laguna Beach). Public domain.