When to plant in Sunnyvale, CA
USDA Zone 10aHere are the average frost dates, USDA hardiness zone, and a month-by-month planting calendar for Sunnyvale, California — all computed from Sunnyvale's nearest NOAA weather station.
With about 351 frost-free days, Sunnyvale supports back-to-back plantings; stagger sowings every few weeks to keep beds productive spring through fall. In zone 10a, frost is a minor factor for Sunnyvale — most perennials thrive, and annual vegetables can go out early and stay late.
The average first fall frost in Sunnyvale is now 7 days earlier than in the 1981–2010 normals. See how frost dates are shifting nationwide →
Frost probability
MOFFETT FEDERAL AIRFIELD · 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 Sunnyvale’s own odds, recorded at MOFFETT FEDERAL AIRFIELD.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | Mar 6 | Feb 6 | Jan 3 | Nov 20 | Dec 6 | Dec 30 |
| 32°F | Feb 4 | Jan 6 | Dec 16 | Dec 3 | Dec 23 | Jan 16 |
| 28°F | Jan 22 | Jan 1 | Dec 16 | Dec 13 | Dec 31 | Jan 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 Sunnyvale, drawn to the day from the local frost dates. The dashed line is today.
Nearby weather stations
3 within 12 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.
Sunnyvale planting FAQ
When is the last spring frost in Sunnyvale, CA?
Sunnyvale's average last spring frost falls near January 6 — 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 Sunnyvale, CA?
The first fall frost in Sunnyvale typically arrives around December 23 (50% probability at 32°F). Harvest or protect frost-sensitive crops before then.
What hardiness zone is Sunnyvale in?
Sunnyvale is in USDA hardiness zone 10a. In zone 10a, winters are mild — many tender perennials overwinter here.
How long is the growing season in Sunnyvale?
Sunnyvale has about 351 frost-free days — a long growing season — between the average last spring frost (January 6) and first fall frost (December 23).
When should I plant tomatoes in Sunnyvale?
For Sunnyvale, sow tomatoes indoors about November 11–November 25 and move the seedlings out around January 13, after the last spring frost.
Never miss a window in Sunnyvale
An email when it’s time to start seeds, transplant, and sow — timed to Sunnyvale’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reach- Mountain View · 5 km
- Santa Clara · 6 km
- Los Altos · 7 km
- Cupertino · 8 km
- Palo Alto · 10 km
- Saratoga · 13 km
- Milpitas · 13 km
- East Palo Alto · 13 km
Frost dates recorded at MOFFETT FEDERAL AIRFIELD, 3 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 Sunnyvale, CA — Frost Dates & Zone 10a." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USW00023244. Retrieved from https://blissgarden.com/california/sunnyvale.