When to plant in Signal Hill, CA
USDA Zone 10bSignal Hill, California frost dates, USDA zone, and a full-year planting calendar, drawn from the nearest NOAA station and tuned to the local season.
A ~-4-day frost-free window makes Signal Hill a short-season garden: choose early varieties and start long-season crops indoors well ahead of the last frost. These dates come from a station roughly 16 km away, the closest with full normals; terrain around Signal Hill (elevation, water, pavement) can move your real frost dates a few days either way. Zone 10b is warm enough that Signal Hill can grow subtropical perennials, and the short (or absent) frost period barely limits the annual calendar.
Frost probability
TORRANCE 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 Signal Hill’s own odds, recorded at TORRANCE AP.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | Mar 5 | Jan 17 | Dec 12 | Dec 1 | Dec 31 | Feb 20 |
| 32°F | Feb 24 | Jan 9 | Dec 4 | Dec 3 | Jan 5 | Feb 22 |
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 Signal Hill, drawn to the day from the local frost dates. The dashed line is today.
Nearby weather stations
3 within 38 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.
Signal Hill planting FAQ
When is the last spring frost in Signal Hill, CA?
Signal Hill's average last spring frost falls near January 9 — 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 Signal Hill, CA?
The first fall frost in Signal Hill typically arrives around January 5 (50% probability at 32°F). Harvest or protect frost-sensitive crops before then.
What hardiness zone is Signal Hill in?
Signal Hill is in USDA hardiness zone 10b. In zone 10b, winters are mild — many tender perennials overwinter here.
How long is the growing season in Signal Hill?
There are roughly -4 frost-free days in Signal Hill (a short growing season), running from the average last frost around January 9 to the first fall frost near January 5.
When should I plant tomatoes in Signal Hill?
In Signal Hill, start tomato seeds indoors around November 14–November 28, then transplant seedlings outdoors around January 16 once the danger of frost has passed.
Never miss a window in Signal Hill
An email when it’s time to start seeds, transplant, and sow — timed to Signal Hill’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reach- Long Beach · 3 km
- Lakewood · 7 km
- Rossmoor · 8 km
- Carson · 8 km
- Hawaiian Gardens · 9 km
- Los Alamitos · 10 km
- Bellflower · 10 km
- East Rancho Dominguez · 10 km
Frost dates recorded at TORRANCE AP, 16 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 Signal Hill, CA — Frost Dates & Zone 10b." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USW00003122. Retrieved from https://blissgarden.com/california/signal-hill.