When to plant in Larkspur, CA
USDA Zone 10aEverything below — frost dates, hardiness zone, and what to plant when in Larkspur, California — is derived from the closest NOAA station with complete climate normals.
With about 336 frost-free days, Larkspur supports back-to-back plantings; stagger sowings every few weeks to keep beds productive spring through fall. Zone 10a is warm enough that Larkspur can grow subtropical perennials, and the short (or absent) frost period barely limits the annual calendar.
The average last spring frost in Larkspur is now 10 days earlier than in the 1981–2010 normals. See how frost dates are shifting nationwide →
Frost probability
KENTFIELD · 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 Larkspur’s own odds, recorded at KENTFIELD.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | Apr 5 | Mar 5 | Jan 29 | Nov 12 | Nov 29 | Dec 21 |
| 32°F | Feb 25 | Jan 16 | Dec 21 | Nov 30 | Dec 18 | Jan 19 |
| 28°F | Jan 23 | Dec 30 | Dec 9 | Dec 4 | Dec 24 | Jan 21 |
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 Larkspur, drawn to the day from the local frost dates. The dashed line is today.
Nearby weather stations
3 within 14 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.
Larkspur planting FAQ
When is the last spring frost in Larkspur, CA?
Larkspur's average last spring frost falls near January 16 — 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 Larkspur, CA?
Expect Larkspur's first fall frost near December 18 — a 50% chance of 32°F by that date. Bring in or cover tender crops ahead of it.
What hardiness zone is Larkspur in?
Larkspur is in USDA hardiness zone 10a. In zone 10a, winters are mild — many tender perennials overwinter here.
How long is the growing season in Larkspur?
There are roughly 336 frost-free days in Larkspur (a long growing season), running from the average last frost around January 16 to the first fall frost near December 18.
When should I plant tomatoes in Larkspur?
In Larkspur, start tomato seeds indoors around November 21–December 5, then transplant seedlings outdoors around January 23 once the danger of frost has passed.
Never miss a window in Larkspur
An email when it’s time to start seeds, transplant, and sow — timed to Larkspur’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reach- Corte Madera · 2 km
- Mill Valley · 4 km
- San Rafael · 5 km
- San Anselmo · 6 km
- Tamalpais-Homestead Valley · 7 km
- Richmond · 15 km
- Novato · 16 km
- San Pablo · 17 km
Frost dates recorded at KENTFIELD, 2 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 Larkspur, CA — Frost Dates & Zone 10a." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USC00044500. Retrieved from https://blissgarden.com/california/larkspur.