Monterey climate

Monterey Frost Dates and Growing Season

NOAA 1991-2020 normals for Monterey, 0.3 km from Monterey, elevation 1860 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Monterey. 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 10 and the first fall freeze around October 30, a growing season of about 203 days.

Median at 36°F
last April 23, first October 21
Median at 32°F
last April 10, first October 30
Median at 28°F
last March 30, first November 9

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°FMay 8May 3Apr 30Apr 27Apr 23Apr 19Apr 16Apr 12Apr 6
32°FApr 28Apr 22Apr 18Apr 13Apr 10Apr 6Apr 3Mar 29Mar 23
28°FApr 17Apr 10Apr 4Apr 1Mar 30Mar 26Mar 21Mar 17Mar 9
24°FApr 5Mar 30Mar 26Mar 21Mar 17Mar 13Mar 9Mar 3Feb 25
20°FMar 26Mar 20Mar 14Mar 9Mar 4Mar 1Feb 24Feb 17Feb 8
16°FMar 18Mar 8Mar 2Feb 27Feb 22Feb 16Feb 10Feb 3Jan 26

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 7Oct 12Oct 16Oct 18Oct 21Oct 24Oct 26Oct 29Nov 1
32°FOct 16Oct 21Oct 25Oct 27Oct 30Nov 1Nov 3Nov 7Nov 13
28°FOct 27Nov 1Nov 3Nov 6Nov 9Nov 13Nov 16Nov 21Nov 29
24°FNov 5Nov 10Nov 14Nov 17Nov 21Nov 25Dec 1Dec 4Dec 9
20°FNov 14Nov 20Nov 26Nov 30Dec 2Dec 6Dec 11Dec 18Dec 26
16°FNov 25Dec 1Dec 8Dec 13Dec 20Dec 25Dec 29Jan 3Jan 11

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°F201194189184180176171166159
32°F227218213208203199194188180
28°F252244237232227223218210201
24°F278267260255250245239232224
20°F306293286278272266260254244
16°F331321312306301294287278268

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
100% 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
4,269
Cooling degree days, base 65°F
1,154
Growing degree days, base 40°F
6,675
Growing degree days, base 45°F
5,269
Growing degree days, base 50°F
4,010
Growing degree days, base 55°F
2,907
Growing degree days, base 60°F
1,955

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January925019
February735025
March570494
April28527246
May9799471
June9224664
July1323787
August2295758
September43154562
October25428274
November543280
December806029

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 0.3 km from Monterey. 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 USC00406170 (Monterey). Public domain.