Ripon climate

Ripon Frost Dates and Growing Season

NOAA 1991-2020 normals for Stockton Metro AP, 18.7 km from Ripon, elevation 26 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Stockton Metro AP. 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 6 and the first fall freeze around December 1, a growing season of about 304 days.

Median at 36°F
last March 10, first November 18
Median at 32°F
last February 6, first December 1
Median at 28°F
last January 10, first December 16

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 7Mar 30Mar 23Mar 15Mar 10Mar 4Feb 28Feb 23Feb 11
32°FFeb 28Feb 23Feb 17Feb 11Feb 6Jan 31Jan 24Jan 14Dec 31
28°FFeb 5Jan 30Jan 25Jan 17Jan 10Jan 5Dec 30Dec 24Dec 14
24°FJan 20Jan 16Jan 11Jan 7Jan 1Dec 29Dec 25Dec 19Dec 12
20°F–––––––––
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°FNov 4Nov 8Nov 12Nov 15Nov 18Nov 21Nov 24Nov 28Dec 2
32°FNov 15Nov 20Nov 24Nov 27Dec 1Dec 3Dec 7Dec 13Dec 26
28°FNov 29Dec 2Dec 7Dec 11Dec 16Dec 20Dec 27Jan 5Jan 14
24°FDec 6Dec 11Dec 17Dec 22Dec 27Dec 31Jan 5Jan 10Jan 15
20°F–––––––––
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°F285273266259253246239230219
32°F339328319310304297290281271
28°F365365359351346339334327315
24°F365365365365365365365359347
20°F365365365365365365365365365
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
99% of years
28°F or colder
77% of years
24°F or colder
30% of years
20°F or colder
4% of years
16°F or colder
0% 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
2,260
Cooling degree days, base 65°F
1,566
Growing degree days, base 40°F
8,439
Growing degree days, base 45°F
6,666
Growing degree days, base 50°F
5,040
Growing degree days, base 55°F
3,646
Growing degree days, base 60°F
2,494

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January525035
February361088
March2701204
April14624330
May41125549
June4274720
July0408873
August0383848
September3271719
October6478479
November3112159
December535037

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 18.7 km from Ripon. 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 USW00023237 (Stockton Metro AP). Public domain.