Oakland climate

Oakland Frost Dates and Growing Season

NOAA 1991-2020 normals for Oakland 1 Se, 0.8 km from Oakland, elevation 2420 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Oakland 1 Se. 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 May 6 and the first fall freeze around October 9, a growing season of about 156 days.

Median at 36°F
last May 17, first September 29
Median at 32°F
last May 6, first October 9
Median at 28°F
last April 24, first October 20

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 31May 27May 24May 20May 17May 13May 10May 6May 1
32°FMay 23May 17May 13May 9May 6May 3Apr 30Apr 26Apr 21
28°FMay 12May 5May 1Apr 28Apr 24Apr 20Apr 17Apr 14Apr 8
24°FApr 29Apr 22Apr 18Apr 14Apr 10Apr 7Apr 4Apr 1Mar 27
20°FApr 15Apr 9Apr 5Apr 3Mar 31Mar 29Mar 25Mar 21Mar 16
16°FApr 5Apr 1Mar 28Mar 24Mar 20Mar 17Mar 14Mar 10Mar 4

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°FSep 15Sep 20Sep 23Sep 26Sep 29Oct 1Oct 4Oct 7Oct 10
32°FSep 26Oct 1Oct 4Oct 6Oct 9Oct 12Oct 15Oct 19Oct 23
28°FOct 5Oct 10Oct 13Oct 17Oct 20Oct 23Oct 26Oct 29Nov 2
24°FOct 16Oct 22Oct 25Oct 29Nov 1Nov 2Nov 5Nov 9Nov 14
20°FOct 27Nov 1Nov 3Nov 6Nov 10Nov 12Nov 16Nov 20Nov 27
16°FNov 4Nov 9Nov 13Nov 16Nov 20Nov 24Nov 29Dec 4Dec 12

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°F156149144139136131126122114
32°F177170164160156152148142136
28°F199192187183179174170164155
24°F223216211207203199194189182
20°F246238232227223219214208201
16°F270261253248244239234229220

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
6,064
Cooling degree days, base 65°F
520
Growing degree days, base 40°F
4,907
Growing degree days, base 45°F
3,725
Growing degree days, base 50°F
2,691
Growing degree days, base 55°F
1,807
Growing degree days, base 60°F
1,079

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,16203
February97904
March845022
April4844106
May22231293
June5399497
July11188642
August21143588
September12749376
October4266129
November732025
December1,00308

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 0.8 km from Oakland. 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 USC00186620 (Oakland 1 Se). Public domain.