When to plant in Riverbank, CA
USDA Zone 9bRiverbank, California frost dates, USDA zone, and a full-year planting calendar, drawn from the nearest NOAA station and tuned to the local season.
A generous ~308-day season lets Riverbank gardeners direct-sow more and still ripen long-maturity crops like melons and winter squash. Zone 9b is warm enough that Riverbank can grow subtropical perennials, and the short (or absent) frost period barely limits the annual calendar.
The average first fall frost in Riverbank is now 7 days earlier than in the 1981–2010 normals. See how frost dates are shifting nationwide →
Frost probability
MODESTO CITY CO AP · 1991–2020The date the last spring and first fall frost occur, by threshold and probability. A 90% date is later in spring — and earlier in fall — than a 10% date; the 50% · 32°F row is what most gardeners plan around. These are Riverbank’s own odds, recorded at MODESTO CITY CO AP.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | Mar 31 | Mar 1 | Feb 3 | Nov 8 | Nov 22 | Dec 9 |
| 32°F | Feb 25 | Jan 31 | Dec 31 | Nov 20 | Dec 5 | Jan 6 |
| 28°F | Feb 6 | Jan 8 | Dec 16 | Dec 1 | Dec 21 | Jan 20 |
Download this table as CSV ↓ — every threshold and probability, plus this city’s planting-window dates.
What to plant now
TODAY · JULY 19Full-year planting calendar
Each bar is the exact window to take a planting action in Riverbank, drawn to the day from the local frost dates. The dashed line is today.
Nearby weather stations
3 within 31 km · complete 32°F normalsWhen stations disagree by more than a few days, that spread is real microclimate variation — elevation, water, urban heat. Judge which station best matches your own yard.
Riverbank planting FAQ
When is the last spring frost in Riverbank, CA?
Riverbank's average last spring frost falls near January 31 — the 50% mark at 32°F in the 1991–2020 normals. Hold tender transplants until the risk has passed, then plant out.
When is the first fall frost in Riverbank, CA?
Expect Riverbank's first fall frost near December 5 — a 50% chance of 32°F by that date. Bring in or cover tender crops ahead of it.
What hardiness zone is Riverbank in?
Riverbank is in USDA hardiness zone 9b. In zone 9b, winters are mild — many tender perennials overwinter here.
How long is the growing season in Riverbank?
There are roughly 308 frost-free days in Riverbank (a long growing season), running from the average last frost around January 31 to the first fall frost near December 5.
When should I plant tomatoes in Riverbank?
In Riverbank, start tomato seeds indoors around December 6–December 20, then transplant seedlings outdoors around February 7 once the danger of frost has passed.
Never miss a window in Riverbank
An email when it’s time to start seeds, transplant, and sow — timed to Riverbank’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reachFrost dates recorded at MODESTO CITY CO AP, 11 km from the city center · 1991–2020 NOAA climate normals · zone from the USDA/PRISM 2023 map. How we compute this.
BlissGarden. "When to Plant in Riverbank, CA — Frost Dates & Zone 9b." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USW00023258. Retrieved from https://blissgarden.com/california/riverbank.