Monterey County climate

Monterey County Frost Dates and Growing Season

NOAA 1991-2020 normals for King City, 15.8 km from Monterey County, elevation 320 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for King City. 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 February 23 and the first fall freeze around November 22, a growing season of about 271 days.

Median at 36°F
last April 7, first November 4
Median at 32°F
last February 23, first November 22
Median at 28°F
last January 22, 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°FApr 29Apr 22Apr 16Apr 11Apr 7Apr 1Mar 27Mar 17Mar 5
32°FMar 31Mar 16Mar 6Feb 28Feb 23Feb 17Feb 9Feb 1Jan 19
28°FFeb 21Feb 10Feb 4Jan 31Jan 22Jan 14Jan 5Dec 30Dec 18
24°FJan 29Jan 16Jan 8Jan 3Dec 31Dec 26Dec 21Dec 15Dec 6
20°FJan 11Jan 2Dec 31Dec 28Dec 23Dec 19Dec 13Dec 9Dec 5
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.

Threshold10%20%30%40%50%60%70%80%90%
36°FOct 17Oct 24Oct 28Nov 1Nov 4Nov 7Nov 11Nov 15Nov 22
32°FNov 1Nov 8Nov 13Nov 18Nov 22Nov 25Nov 30Dec 3Dec 11
28°FNov 19Nov 25Nov 30Dec 2Dec 6Dec 11Dec 18Dec 30Jan 10
24°FDec 1Dec 4Dec 7Dec 13Dec 17Dec 23Dec 30Jan 3Jan 15
20°FDec 3Dec 5Dec 10Dec 14Dec 21Dec 24Dec 28Jan 1Jan 8
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.

Threshold10%20%30%40%50%60%70%80%90%
36°F245234226218213207201195184
32°F308295285278271264256246233
28°F357346338331326319310300287
24°F365365365365362354346338331
20°F365365365365365365365365357
16°F365365365365365365365365365

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
92% of years
24°F or colder
54% of years
20°F or colder
13% of years
16°F or colder
1% 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
2,288
Cooling degree days, base 65°F
578
Growing degree days, base 40°F
7,418
Growing degree days, base 45°F
5,621
Growing degree days, base 50°F
3,940
Growing degree days, base 55°F
2,495
Growing degree days, base 60°F
1,373

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January440076
February3420105
March2782199
April19311270
May10438398
June2984506
July4138600
August3141603
September18117549
October10144408
November2993172
December479054

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 15.8 km from Monterey County. Low ground, valleys and open fields freeze earlier and later than a town center or a hillside.

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Sources

NOAA NCEI U.S. Climate Normals, 1991-2020, annual and seasonal normals for station USC00044555 (King City). Public domain.