Aguanga climate

Aguanga Frost Dates and Growing Season

NOAA 1991-2020 normals for Palomar Mtn Obsy, 7.6 km from Aguanga, elevation 5550 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Palomar Mtn Obsy. 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 29 and the first fall freeze around November 18, a growing season of about 201 days.

Median at 36°F
last May 19, first November 1
Median at 32°F
last April 29, first November 18
Median at 28°F
last April 5, first December 6

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 7Jun 1May 29May 24May 19May 13May 6Apr 30Apr 23
32°FMay 29May 18May 10May 3Apr 29Apr 24Apr 17Apr 11Apr 2
28°FMay 5Apr 27Apr 18Apr 11Apr 5Mar 29Mar 21Mar 11Feb 26
24°FApr 15Apr 1Mar 22Mar 13Mar 4Feb 25Feb 16Feb 1Jan 6
20°FMar 26Mar 7Feb 26Feb 18Feb 11Jan 31Jan 19Jan 5Dec 26
16°FFeb 23Feb 19Feb 14Feb 11Feb 7Feb 3Jan 25Jan 11Jan 4

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 10Oct 16Oct 22Oct 27Nov 1Nov 5Nov 10Nov 14Nov 21
32°FOct 27Nov 2Nov 8Nov 13Nov 18Nov 22Nov 27Dec 2Dec 8
28°FNov 10Nov 19Nov 27Dec 1Dec 6Dec 10Dec 15Dec 20Dec 31
24°FNov 30Dec 7Dec 13Dec 19Dec 25Jan 1Jan 11Jan 28Feb 19
20°FDec 12Dec 26Jan 1Jan 6Jan 20Jan 29Feb 10Feb 19Mar 8
16°FJan 2Jan 10Jan 24Feb 1Feb 6Feb 8Feb 13Feb 18Feb 22

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°F201188179171165160154146137
32°F236225216208201193184175164
28°F285271259250243234225214201
24°F351326312303291280272262248
20°F365365365365355334319306284
16°F365365365365365365365365362

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
95% of years
20°F or colder
54% of years
16°F or colder
11% 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
3,835
Cooling degree days, base 65°F
981
Growing degree days, base 40°F
6,500
Growing degree days, base 45°F
4,997
Growing degree days, base 50°F
3,690
Growing degree days, base 55°F
2,588
Growing degree days, base 60°F
1,696

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January643030
February601035
March548176
April4073138
May23343308
June63145536
July3285747
August2295758
September37169583
October19438330
November4423115
December662033

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 7.6 km from Aguanga. 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 USC00046657 (Palomar Mtn Obsy). Public domain.