Lytle Creek climate

Lytle Creek Frost Dates and Growing Season

NOAA 1991-2020 normals for Wrightwood, 17.1 km from Lytle Creek, elevation 6000 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Wrightwood. 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 May 16 and the first fall freeze around October 13, a growing season of about 151 days.

Median at 36°F
last June 4, first October 1
Median at 32°F
last May 16, first October 13
Median at 28°F
last April 25, first October 30

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 20Jun 15Jun 11Jun 8Jun 4Jun 1May 28May 23May 14
32°FJun 9Jun 3May 29May 22May 16May 10May 4Apr 30Apr 25
28°FMay 13May 4May 1Apr 28Apr 25Apr 21Apr 17Apr 12Apr 6
24°FApr 25Apr 19Apr 13Apr 9Apr 4Mar 29Mar 22Mar 15Mar 7
20°FApr 12Apr 2Mar 22Mar 13Mar 7Mar 2Feb 26Feb 19Feb 9
16°FMar 13Mar 2Feb 25Feb 20Feb 14Feb 6Jan 29Jan 15Dec 31

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°FSep 10Sep 19Sep 24Sep 29Oct 1Oct 4Oct 7Oct 11Oct 17
32°FSep 25Oct 1Oct 5Oct 9Oct 13Oct 16Oct 20Oct 25Nov 1
28°FOct 10Oct 15Oct 20Oct 26Oct 30Nov 2Nov 5Nov 8Nov 13
24°FOct 22Oct 30Nov 4Nov 8Nov 12Nov 16Nov 20Nov 25Dec 1
20°FNov 7Nov 16Nov 20Nov 25Nov 29Dec 2Dec 6Dec 12Dec 20
16°FNov 23Nov 29Dec 4Dec 11Dec 17Dec 25Jan 1Jan 17Feb 3

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°F14613613012511911410910393
32°F178169162157151144137131122
28°F209202195190186180175169160
24°F255243235228222216210203193
20°F299286279272265258248238225
16°F358340329320309302292282269

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
100% of years
20°F or colder
100% of years
16°F or colder
95% 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
5,692
Cooling degree days, base 65°F
237
Growing degree days, base 40°F
4,250
Growing degree days, base 45°F
3,027
Growing degree days, base 50°F
2,050
Growing degree days, base 55°F
1,266
Growing degree days, base 60°F
653

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January88100
February79901
March71909
April565038
May3452166
June13520339
July22111555
August3586516
September14917325
October448193
November69608
December89701

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 17.1 km from Lytle Creek. 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 USC00049822 (Wrightwood). Public domain.