Pine Valley climate

Pine Valley Frost Dates and Growing Season

NOAA 1991-2020 normals for Mt Laguna #3, 11.5 km from Pine Valley, elevation 5920 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Mt Laguna #3. 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 8, a growing season of about 197 days.

Median at 36°F
last May 10, first October 23
Median at 32°F
last April 22, first November 8
Median at 28°F
last April 2, 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°FJun 2May 29May 22May 16May 10May 2Apr 29Apr 23Apr 15
32°FMay 21May 13May 4Apr 29Apr 22Apr 15Apr 10Apr 3Mar 25
28°FMay 8Apr 28Apr 19Apr 10Apr 2Mar 27Mar 18Mar 8Feb 22
24°FApr 21Apr 4Mar 23Mar 12Mar 2Feb 23Feb 8Jan 27Jan 9
20°FMar 21Feb 28Feb 18Feb 10Feb 1Jan 22Jan 13Jan 5Dec 25
16°FFeb 23Feb 13Feb 7Jan 30Jan 23Jan 16Jan 11Jan 6Jan 1

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 1Oct 6Oct 11Oct 17Oct 23Oct 29Nov 2Nov 7Nov 13
32°FOct 10Oct 21Oct 30Nov 4Nov 8Nov 12Nov 18Nov 25Dec 4
28°FNov 2Nov 10Nov 17Nov 24Dec 1Dec 5Dec 10Dec 17Dec 25
24°FNov 18Dec 1Dec 9Dec 15Dec 20Dec 27Jan 2Jan 12Jan 30
20°FDec 11Dec 20Dec 28Jan 2Jan 8Jan 15Jan 26Feb 7Feb 23
16°FDec 31Jan 4Jan 8Jan 13Jan 19Jan 25Feb 2Feb 11Feb 19

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°F195184177171164159150142131
32°F232221211204197189181173163
28°F286267256246236227217208195
24°F345326311301288277265251234
20°F365365365358344333320309293
16°F365365365365365365365355328

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
97% of years
20°F or colder
69% of years
16°F or colder
29% 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
4,361
Cooling degree days, base 65°F
537
Growing degree days, base 40°F
5,596
Growing degree days, base 45°F
4,145
Growing degree days, base 50°F
2,908
Growing degree days, base 55°F
1,907
Growing degree days, base 60°F
1,131

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January722010
February647020
March612039
April4361101
May27120248
June7080461
July6196656
August6167626
September6966449
October2867215
November529063
December707020

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

More

Sources

NOAA NCEI U.S. Climate Normals, 1991-2020, annual and seasonal normals for station USC00045968 (Mt Laguna #3). Public domain.