When to plant in Highland, CA
USDA Zone 10aHighland, California frost dates, USDA zone, and a full-year planting calendar, drawn from the nearest NOAA station and tuned to the local season.
Highland enjoys a long ~326-day frost-free season — you can succession-sow, fit in a second crop, and grow long-season heat-lovers with room to spare. Zone 10a is warm enough that Highland can grow subtropical perennials, and the short (or absent) frost period barely limits the annual calendar.
Frost probability
REDLANDS · 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 Highland’s own odds, recorded at REDLANDS.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | Apr 5 | Mar 2 | Jan 31 | Nov 17 | Dec 2 | Dec 19 |
| 32°F | Feb 28 | Jan 27 | Dec 21 | Dec 1 | Dec 19 | Jan 26 |
| 28°F | Feb 15 | Jan 7 | Dec 17 | Dec 13 | Jan 1 | Feb 13 |
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 Highland, drawn to the day from the local frost dates. The dashed line is today.
Nearby weather stations
3 within 24 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.
Highland planting FAQ
When is the last spring frost in Highland, CA?
Highland's average last spring frost falls near January 27 — 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 Highland, CA?
The first fall frost in Highland typically arrives around December 19 (50% probability at 32°F). Harvest or protect frost-sensitive crops before then.
What hardiness zone is Highland in?
Highland is in USDA hardiness zone 10a. In zone 10a, winters are mild — many tender perennials overwinter here.
How long is the growing season in Highland?
There are roughly 326 frost-free days in Highland (a long growing season), running from the average last frost around January 27 to the first fall frost near December 19.
When should I plant tomatoes in Highland?
In Highland, start tomato seeds indoors around December 2–December 16, then transplant seedlings outdoors around February 3 once the danger of frost has passed.
Never miss a window in Highland
An email when it’s time to start seeds, transplant, and sow — timed to Highland’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reach- Redlands · 7 km
- Loma Linda · 11 km
- San Bernardino · 12 km
- Yucaipa · 14 km
- Lake Arrowhead · 16 km
- Colton · 16 km
- Grand Terrace · 16 km
- Muscoy · 17 km
Frost dates recorded at REDLANDS, 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 Highland, CA — Frost Dates & Zone 10a." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USC00047306. Retrieved from https://blissgarden.com/california/highland.