Eldridge climate

Eldridge Frost Dates and Growing Season

NOAA 1991-2020 normals for Sonoma, 7 km from Eldridge, elevation 97 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Sonoma. 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 March 2 and the first fall freeze around November 27, a growing season of about 270 days.

Median at 36°F
last April 8, first November 8
Median at 32°F
last March 2, first November 27
Median at 28°F
last January 20, first December 14

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 24Apr 18Apr 14Apr 8Apr 3Mar 30Mar 24Mar 14
32°FApr 5Mar 23Mar 13Mar 6Mar 2Feb 25Feb 17Feb 7Jan 27
28°FFeb 22Feb 11Feb 1Jan 27Jan 20Jan 12Jan 4Dec 29Dec 20
24°FJan 29Jan 16Jan 10Jan 5Jan 1Dec 30Dec 23Dec 16Dec 10
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°FOct 25Oct 30Nov 1Nov 4Nov 8Nov 10Nov 14Nov 19Nov 26
32°FNov 6Nov 12Nov 18Nov 23Nov 27Dec 1Dec 4Dec 10Dec 21
28°FNov 24Dec 1Dec 5Dec 9Dec 14Dec 19Dec 27Jan 4Jan 17
24°FDec 3Dec 10Dec 15Dec 21Dec 28Dec 31Jan 4Jan 10Jan 23
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°F247234227221214209203197187
32°F310297287278270263254243230
28°F365354346338334325315305292
24°F365365365365365365360350338
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
100% of years
28°F or colder
87% of years
24°F or colder
36% of years
20°F or colder
2% 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
2,748
Cooling degree days, base 65°F
581
Growing degree days, base 40°F
6,965
Growing degree days, base 45°F
5,196
Growing degree days, base 50°F
3,608
Growing degree days, base 55°F
2,308
Growing degree days, base 60°F
1,307

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January536026
February396067
March3531135
April2565205
May14033359
June3697512
July6153612
August5149609
September18108540
October11233386
November3461131
December544027

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 km from Eldridge. 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 USC00048351 (Sonoma). Public domain.