When to plant in Clearlake, CA
USDA Zone 9aHere are the average frost dates, USDA hardiness zone, and a month-by-month planting calendar for Clearlake, California — all computed from Clearlake's nearest NOAA weather station.
In zone 9a, frost is a minor factor for Clearlake — most perennials thrive, and annual vegetables can go out early and stay late.
Frost probability
CLEARLAKE 4 SE · 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 Clearlake’s own odds, recorded at CLEARLAKE 4 SE.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | May 16 | Apr 30 | Apr 14 | Oct 11 | Oct 27 | Nov 7 |
| 32°F | Apr 30 | Apr 10 | Mar 24 | Oct 24 | Nov 6 | Nov 20 |
| 28°F | Apr 7 | Mar 14 | Feb 12 | Nov 4 | Nov 21 | Dec 8 |
Download this table as CSV ↓ — every threshold and probability, plus this city’s planting-window dates.
What to plant now
TODAY · JULY 19Full-year planting calendar
Each bar is the exact window to take a planting action in Clearlake, drawn to the day from the local frost dates. The dashed line is today.
Nearby weather stations
3 within 41 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.
Clearlake planting FAQ
When is the last spring frost in Clearlake, CA?
Clearlake's average last spring frost falls near April 10 — 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 Clearlake, CA?
In Clearlake, the first 32°F freeze of fall lands around November 6 on average. Time your last harvests and any season-extension cover before it.
What hardiness zone is Clearlake in?
Clearlake is in USDA hardiness zone 9a. In zone 9a, winters are mild — many tender perennials overwinter here.
How long is the growing season in Clearlake?
Clearlake has about 210 frost-free days — a moderate growing season — between the average last spring frost (April 10) and first fall frost (November 6).
When should I plant tomatoes in Clearlake?
For Clearlake, sow tomatoes indoors about February 13–February 27 and move the seedlings out around April 17, after the last spring frost.
Never miss a window in Clearlake
An email when it’s time to start seeds, transplant, and sow — timed to Clearlake’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reach- Healdsburg · 43 km
- Windsor · 49 km
- Ukiah · 54 km
- Santa Rosa · 58 km
- Rohnert Park · 68 km
- Sonoma · 76 km
- Napa · 79 km
- Petaluma · 80 km
Frost dates recorded at CLEARLAKE 4 SE, 7 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 Clearlake, CA — Frost Dates & Zone 9a." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USC00041806. Retrieved from https://blissgarden.com/california/clearlake.