When to plant in Hercules, CA
USDA Zone 9bHercules, California frost dates, USDA zone, and a full-year planting calendar, drawn from the nearest NOAA station and tuned to the local season.
Hercules enjoys a long ~344-day frost-free season — you can succession-sow, fit in a second crop, and grow long-season heat-lovers with room to spare. Zone 9b is warm enough that Hercules can grow subtropical perennials, and the short (or absent) frost period barely limits the annual calendar.
Frost probability
VALLEJO · 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 Hercules’s own odds, recorded at VALLEJO.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | Apr 8 | Mar 4 | Jan 19 | Nov 21 | Dec 7 | Jan 2 |
| 32°F | Mar 4 | Jan 17 | Dec 23 | Dec 4 | Dec 27 | Feb 4 |
| 28°F | Jan 19 | Jan 5 | Dec 19 | Dec 13 | Jan 2 | Jan 19 |
Download this table as CSV ↓ — every threshold and probability, plus this city’s planting-window dates.
What to plant now
TODAY · JULY 19Nothing new to sow or transplant outdoors in the next few weeks — a seasonal lull. Check the full-year calendar below for the next window.
Full-year planting calendar
Each bar is the exact window to take a planting action in Hercules, drawn to the day from the local frost dates. The dashed line is today.
Nearby weather stations
3 within 15 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.
Hercules planting FAQ
When is the last spring frost in Hercules, CA?
On average, the last spring frost in Hercules is around January 17 (50% probability at 32°F, from 1991–2020 NOAA normals). Wait until after this date to set out tender plants like tomatoes and peppers.
When is the first fall frost in Hercules, CA?
In Hercules, the first 32°F freeze of fall lands around December 27 on average. Time your last harvests and any season-extension cover before it.
What hardiness zone is Hercules in?
Hercules is in USDA hardiness zone 9b. In zone 9b, winters are mild — many tender perennials overwinter here.
How long is the growing season in Hercules?
There are roughly 344 frost-free days in Hercules (a long growing season), running from the average last frost around January 17 to the first fall frost near December 27.
When should I plant tomatoes in Hercules?
In Hercules, start tomato seeds indoors around November 22–December 6, then transplant seedlings outdoors around January 24 once the danger of frost has passed.
Never miss a window in Hercules
An email when it’s time to start seeds, transplant, and sow — timed to Hercules’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reach- Pinole · 3 km
- El Sobrante · 5 km
- San Pablo · 8 km
- Vallejo · 10 km
- Richmond · 10 km
- El Cerrito · 11 km
- Benicia · 13 km
- Albany · 15 km
Frost dates recorded at VALLEJO, 12 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 Hercules, CA — Frost Dates & Zone 9b." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USC00049219. Retrieved from https://blissgarden.com/california/hercules.