Stockton climate

Stockton Frost Dates and Growing Season

NOAA 1991-2020 normals for Stockton Dam, 2.1 km from Stockton, elevation 922 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Stockton Dam. 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 6 and the first fall freeze around October 30, a growing season of about 207 days.

Median at 36°F
last April 16, first October 21
Median at 32°F
last April 6, first October 30
Median at 28°F
last March 27, first November 8

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 4Apr 28Apr 24Apr 20Apr 16Apr 13Apr 10Apr 6Apr 1
32°FApr 23Apr 17Apr 12Apr 9Apr 6Apr 2Mar 31Mar 26Mar 21
28°FApr 10Apr 5Apr 2Mar 30Mar 27Mar 23Mar 20Mar 15Mar 9
24°FApr 1Mar 26Mar 22Mar 18Mar 15Mar 12Mar 8Mar 3Feb 27
20°FMar 20Mar 16Mar 12Mar 8Mar 4Mar 2Feb 27Feb 22Feb 14
16°FMar 13Mar 7Mar 3Mar 1Feb 25Feb 20Feb 15Feb 10Feb 2

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 6Oct 12Oct 16Oct 18Oct 21Oct 23Oct 26Oct 29Nov 2
32°FOct 17Oct 21Oct 25Oct 27Oct 30Nov 1Nov 4Nov 8Nov 14
28°FOct 26Oct 31Nov 2Nov 5Nov 8Nov 12Nov 15Nov 20Nov 27
24°FNov 2Nov 7Nov 11Nov 15Nov 19Nov 24Nov 29Dec 2Dec 8
20°FNov 8Nov 15Nov 21Nov 26Nov 30Dec 4Dec 7Dec 13Dec 18
16°FNov 18Nov 27Dec 1Dec 5Dec 10Dec 15Dec 19Dec 24Jan 1

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°F206199194190185181175170163
32°F228219214210207201198192184
28°F252244237233228224219213205
24°F274266259253249244239234225
20°F295286280275270265259252245
16°F317306299293288283277270260

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
4,324
Cooling degree days, base 65°F
1,632
Growing degree days, base 40°F
7,128
Growing degree days, base 45°F
5,739
Growing degree days, base 50°F
4,495
Growing degree days, base 55°F
3,398
Growing degree days, base 60°F
2,443

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January98706
February770018
March571284
April27621238
May86124506
June5322766
July0467931
August1435899
September37211625
October22547315
November523492
December843016

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 2.1 km from Stockton. 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 USC00238082 (Stockton Dam). Public domain.