When to plant in Fontana, CA
USDA Zone 10aFontana, California frost dates, USDA zone, and a full-year planting calendar, drawn from the nearest NOAA station and tuned to the local season.
Fontana enjoys a long ~360-day frost-free season — you can succession-sow, fit in a second crop, and grow long-season heat-lovers with room to spare. In zone 10a, frost is a minor factor for Fontana — most perennials thrive, and annual vegetables can go out early and stay late.
Frost probability
ONTARIO INTL 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 Fontana’s own odds, recorded at ONTARIO INTL AP.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | Feb 28 | Jan 27 | Dec 24 | Nov 27 | Dec 17 | Jan 17 |
| 32°F | Feb 7 | Jan 4 | Dec 14 | Dec 11 | Dec 30 | Feb 1 |
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 Fontana, drawn to the day from the local frost dates. The dashed line is today.
Nearby weather stations
3 within 18 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.
Fontana planting FAQ
When is the last spring frost in Fontana, CA?
Fontana's average last spring frost falls near January 4 — 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 Fontana, CA?
The first fall frost in Fontana typically arrives around December 30 (50% probability at 32°F). Harvest or protect frost-sensitive crops before then.
What hardiness zone is Fontana in?
Fontana is in USDA hardiness zone 10a. In zone 10a, winters are mild — many tender perennials overwinter here.
How long is the growing season in Fontana?
Fontana has about 360 frost-free days — a long growing season — between the average last spring frost (January 4) and first fall frost (December 30).
When should I plant tomatoes in Fontana?
For Fontana, sow tomatoes indoors about November 9–November 23 and move the seedlings out around January 11, after the last spring frost.
Never miss a window in Fontana
An email when it’s time to start seeds, transplant, and sow — timed to Fontana’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reach- Rialto · 7 km
- Bloomington · 8 km
- Rancho Cucamonga · 10 km
- Muscoy · 12 km
- Jurupa Valley · 12 km
- Colton · 14 km
- Ontario · 15 km
- San Bernardino · 16 km
Frost dates recorded at ONTARIO INTL AP, 14 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 Fontana, CA — Frost Dates & Zone 10a." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USW00003102. Retrieved from https://blissgarden.com/california/fontana.