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

Frost leaves San Bernardino on January 27 and comes back on December 19 when the odds are even, a window of 329 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 February 28, and one fall in ten has its first freeze by December 1. Against a median of 229 days for the 100 cities on these pages, San Bernardino has a season 100 days longer, 12th on the list.

The numbers belong to Redlands, NOAA station USC00047306, which sits 9.2 miles south-east of the Census Bureau's internal point for San Bernardino at an elevation of about 1,400 feet.

Last spring frost in San Bernardino

Read the table from the top: a freeze on or after February 28 is a one-in-ten winter, after January 27 is a coin toss, and after December 21 is the usual case.

The earliest and latest of these dates are 69 days apart, wider than for most of the 100 cities here. A freeze can still come 32 days after the typical date in San Bernardino, which is why the late date matters more here than in most places.

First fall frost in San Bernardino

NOAA's early fall date for San Bernardino is December 1, its even-odds date is December 19 and its late date is January 26; the first freeze has come by each of them in one, five and nine years out of ten.

56 days separate the early and late fall dates, a broad band compared with most cities here, so a fall crop in San Bernardino should be planned against the early date, not the typical one.

The growing season in San Bernardino

With a season well beyond the middle of these pages, San Bernardino has days to spare for slow crops, as the planting dates below show. Season length swings more here than in most of the 100 cities: 329 days in a typical year, 292 days in a short one, a difference of 37 days.

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. Frost is not guaranteed: 87.7% of years reach 32°F at Redlands, and the other 12.3% never do, so read the dates as when a frost can happen, not as an appointment.

When a hard freeze reaches San Bernardino

A wide gap separates 32°F from 28°F here: the typical hard freeze arrives 13 days after the first frost in fall (January 1) and leaves 20 days before the last in spring (January 7). Frost-tolerant crops get a long extension at both ends. One spring in ten still has a 28°F night on or after February 15, and one fall in ten sees the first by December 13.

What this means for planting in San Bernardino

University of New Hampshire Extension sorts vegetables by how they cope with cold. Cool-season crops go out before the last frost: counting from January 27, cabbage transplants go in on December 30 and lettuce from December 30 to January 6. Tender crops wait until it has passed, with peppers going out on February 10 and beans sown on or after January 27. Peas are the exception to the count: University of New Hampshire Extension says to plant them as soon as the soil thaws, whatever the frost date.

The late date, February 28, falls 32 days after the typical one, so counting from it pushes every tender crop back by more than three weeks. In San Bernardino that is a real choice between earlier planting with cover on hand and later planting with none.

In San Bernardino the fall count works for every crop in the planner: NC State Extension's days to harvest, plus University of Georgia Extension's harvest allowance of 18 days, still leaves a last planting day in July or later for all 34. Of the crops that fit, parsnips is the slowest: 148 days from planting to the early frost, which makes July 6 its last day.

Worked example: the last day for fall broccoli in San Bernardino

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 Bernardino the last planting day is September 12 against the typical first frost on December 19, and August 25 against the early date on December 1.

18 days separate the two last days, enough that in San Bernardino the earlier one is worth following.

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 27 in San Bernardino that means on December 30.

About the Redlands station

At 9.2 miles south-east, the station is some distance from San Bernardino, so parts of the city may not match its record.

At about 1,400 feet, it ranks above 79 and below 20 of the 100 stations used for these pages. In NOAA's file the record is marked R, meaning representative.

No elevation is available for San Bernardino 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.

Nearby cities and their frost dates

Riverside, CA is a short hop at 15 miles; the other two cities below are farther out, so the list moves from local to regional. Elevation differs: the station for Riverside is 560 feet below the one for San Bernardino, which is worth remembering when you compare them.

• Riverside, CA, 15 miles to the south: last frost January 9, first frost December 25, 353 days frost-free; spring frost ends 18 days sooner than in San Bernardino, and the season runs 24 days longer.
• Bakersfield, CA (130 miles, north-west): the last frost is 4 days later than in San Bernardino, and the frost-free season is 17 days shorter than San Bernardino's. Its typical dates are January 31 and December 8, with 312 days frost-free.
• Henderson, NV lies 182 miles north-east of San Bernardino. Typical last frost January 20, first frost December 15, 333 days between; spring frost ends 7 days sooner than in San Bernardino, and frost-free days differ from San Bernardino's by less than a week.

Take these dates further

The frost dates tool opens on this station and lists every probability date, not just the ones above. From there, the spring planting planner and fall planting planner turn the dates into crop lists for San Bernardino, and the hardiness zone lookup answers what will overwinter.

Every city covered is on the city frost dates index, sorted 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

The frost and freeze dates are NOAA's U.S. Climate Normals for 1991–2020 (doi:10.25921/4ek7-fk11), copied from the station's own record without adjustment; NOAA's documentation defines each probability. The Census Bureau's 2024 Gazetteer places San Bernardino on the map, and its Vintage 2024 estimates, 224,775 people here, decide which cities get a page.

The planting dates apply the count rules in University of New Hampshire Extension, NC State Extension and University of Georgia Extension to this station's dates, with nothing added. See how we source every figure for the checks behind them.

These dates describe odds over many years, not next week's weather. Look at the forecast before you plant, and keep a sheet or row cover ready for a night that does not follow the odds.