When to plant in Rancho Cucamonga, CA
USDA Zone 10aEverything below — frost dates, hardiness zone, and what to plant when in Rancho Cucamonga, California — is derived from the closest NOAA station with complete climate normals.
Rancho Cucamonga 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 Rancho Cucamonga — 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 Rancho Cucamonga’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 Rancho Cucamonga, drawn to the day from the local frost dates. The dashed line is today.
Nearby weather stations
3 within 19 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.
Rancho Cucamonga planting FAQ
When is the last spring frost in Rancho Cucamonga, CA?
On average, the last spring frost in Rancho Cucamonga is around January 4 (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 Rancho Cucamonga, CA?
Expect Rancho Cucamonga's first fall frost near December 30 — a 50% chance of 32°F by that date. Bring in or cover tender crops ahead of it.
What hardiness zone is Rancho Cucamonga in?
Rancho Cucamonga is in USDA hardiness zone 10a. In zone 10a, winters are mild — many tender perennials overwinter here.
How long is the growing season in Rancho Cucamonga?
Rancho Cucamonga 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 Rancho Cucamonga?
For Rancho Cucamonga, 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 Rancho Cucamonga
An email when it’s time to start seeds, transplant, and sow — timed to Rancho Cucamonga’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reach- Upland · 9 km
- Fontana · 10 km
- Ontario · 11 km
- Claremont · 14 km
- Montclair · 14 km
- Rialto · 16 km
- Jurupa Valley · 17 km
- Bloomington · 17 km
Frost dates recorded at ONTARIO INTL AP, 9 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 Rancho Cucamonga, CA — Frost Dates & Zone 10a." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USW00003102. Retrieved from https://blissgarden.com/california/rancho-cucamonga.