San Jose, CA Frost Dates: Last Spring and First Fall Frost

Frost leaves San Jose on January 2 and comes back on December 25 when the odds are even, a window of 362 days for tender plants.

Even odds are a coin toss, so plan around the safer edges: one winter in ten still has a freeze on or after January 23, and one fall in ten has its first freeze by December 4. San Jose's season is 133 days longer than the 229 days median across the 100 cities on these pages, which puts it 1st for season length.

Behind every date on this page is one weather station, San Jose (NOAA USC00047821), 6.1 miles north-west of San Jose's internal point in the Census Bureau's files and about 70 feet up.

San Jose's last spring frost, by chance

One year in ten has a freeze on or after January 23. In nine years out of ten there is still a freeze on or after December 14, and half of years see one on or after January 2.

A span of 40 days from the 90% date to the 10% date is wide for these pages. Spring in San Jose is less predictable than in most of the 100 cities, and the late date is 21 days past the typical one.

When is the first frost in San Jose?

Expect the first freeze of fall by December 25 in a typical year. One year in ten brings it by December 4, and nine in ten have had it by January 14.

From the 10% date to the 90% date is 41 days, a wide band here, and the early date arrives 21 days before the typical one.

How long is the frost-free season in San Jose?

With a season well beyond the middle of these pages, San Jose has days to spare for slow crops, as the planting dates below show. A typical year gives 362 days, but nine years in ten still give at least 335 days; 27 days separate the two, a larger swing than most cities here show, so a crop that needs the full typical season is a gamble in San Jose.

The season lengths come from NOAA's simulated years, not from subtracting one typical date from the other, so the two will not match to the day. A night at or below 32°F shows up in only 56.2% of years here. In the remaining 43.8% winter passes without one, so these dates describe when frost is possible, not when it is certain.

Hard freeze dates for San Jose

NOAA computes 28°F dates only where at least one year in ten reaches that low, and at San Jose just 8.4% of years do. A hard freeze is a rare event in San Jose, so there is no typical date to plan around; the 32°F dates above are the ones that matter, and a cover kept handy covers the odd cold night.

Planting dates for San Jose, counted from the frost dates

Counting from January 2, University of New Hampshire Extension puts cabbage transplants out on December 5 and lettuce from December 5 to December 12, ahead of the last frost, and holds peppers until January 16 and beans until January 2 or later. The University of New Hampshire Extension sheet gives peas no frost count at all; sow them as soon as the soil thaws.

From the late date, January 23, every tender crop moves back 21 days; that buys protection against a spring only one year in ten brings.

For fall, NC State Extension gives each crop's days to harvest, and University of Georgia Extension adds a harvest allowance of 18 days; you count back that total from the first frost. Every one of the 34 fall crops in the fall planner still has a last planting day on or after July in San Jose. The slowest crop that still fits is parsnips, at 148 days, and it has to be planted by July 9 to beat the early date.

Worked example: planting broccoli for fall in San Jose

Broccoli transplants need up to 80 days to reach harvest by NC State Extension's table, and University of Georgia Extension adds 18 days to harvest, so 98 days must pass before frost. In San Jose the last planting day is September 18 against the typical first frost on December 25, and August 28 against the early date on December 4.

That is 21 days between the typical and the early schedule; broccoli planted on the later of them risks a frost before harvest in one fall out of ten.

The same crop family has a spring clock too. University of New Hampshire Extension sets cabbage out ahead of the last frost, and from January 2 in San Jose that means on December 5.

About the San Jose station

The station lies 6.1 miles north-west of San Jose's internal point, farther than most on these pages, so treat its dates as a regional guide.

At about 70 feet, it ranks above 17 and below 82 of the 100 stations used for these pages. Its completeness flag is R, which NOAA uses for a representative record.

No elevation is available for San Jose in the Census data we saved, so the station's height may or may not match your garden's. Compare nearby stations in the frost dates tool if it does not, and err toward the colder dates.

San Jose compared with nearby cities

Three cities on these pages lie within a hundred miles of San Jose, the nearest Modesto, CA at 50 miles, which makes the comparison below a close one.

• Modesto, CA, 50 miles to the north-east: last frost January 31, first frost December 5, 312 days frost-free; the last frost is 29 days later than in San Jose, and the season runs 50 days shorter.
• Stockton, CA (55 miles, north-east): spring frost lingers 34 days longer than in San Jose, and it has 57 days less without frost. Its typical dates are February 5 and December 8, with 305 days frost-free.
• Sacramento, CA (90 miles, north): its last frost comes 10 days after San Jose's, and it has 21 days less without frost. Its typical dates are January 12 and December 16, with 341 days frost-free.

Take these dates further

Start with the spring planting planner for the whole crop list counted from these dates, and the fall planting planner for the last planting days. The frost dates tool shows every level of risk at this station, and the hardiness zone lookup covers winter survival for shrubs and perennials.

Looking for another city? The city frost dates index lists every page, grouped by state.

For California, the state planting pages copy the Extension calendar (UC Master Gardener Program) crop by crop and region by region: tomatoes in California, peppers in California, cucumbers in California, summer squash in California, green beans in California. Set those windows beside the frost dates above.

Where these numbers come from

Every frost and freeze date comes from the station's entry in NOAA's U.S. Climate Normals for 1991–2020 (doi:10.25921/4ek7-fk11), with no adjustment, and NOAA's documentation explains what each probability means. The Census Bureau's 2024 Gazetteer places San Jose on the map, and its Vintage 2024 estimates, 997,368 people here, decide which cities get a page.

Planting dates here are those rules from University of New Hampshire Extension, NC State Extension and University of Georgia Extension, applied to this station's frost dates and nothing else. The methodology page explains how each figure is checked.

NOAA's dates say how often frost has come, not when it will. Check the forecast before planting and keep a cover on hand.