When to plant in Los Osos, CA
USDA Zone 10aLos Osos, California frost dates, USDA zone, and a full-year planting calendar, drawn from the nearest NOAA station and tuned to the local season.
Los Osos's growing season is short at roughly -5 days, so succession planting is limited; lean on transplants over direct sowing for anything slow to mature. Zone 10a is warm enough that Los Osos can grow subtropical perennials, and the short (or absent) frost period barely limits the annual calendar.
Frost probability
MORRO BAY FIRE DEPT · 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 Los Osos’s own odds, recorded at MORRO BAY FIRE DEPT.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | Feb 21 | Jan 21 | Dec 18 | Dec 8 | Dec 31 | Feb 4 |
| 32°F | Feb 9 | Jan 19 | Dec 30 | Dec 25 | Jan 14 | Feb 8 |
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 Los Osos, drawn to the day from the local frost dates. The dashed line is today.
Nearby weather stations
3 within 18 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.
Los Osos planting FAQ
When is the last spring frost in Los Osos, CA?
Plan for the last spring frost in Los Osos around January 19 (the date it has a 50% chance of a 32°F freeze). Anything frost-sensitive should go out after it.
When is the first fall frost in Los Osos, CA?
In Los Osos, the first 32°F freeze of fall lands around January 14 on average. Time your last harvests and any season-extension cover before it.
What hardiness zone is Los Osos in?
Los Osos is in USDA hardiness zone 10a. In zone 10a, winters are mild — many tender perennials overwinter here.
How long is the growing season in Los Osos?
There are roughly -5 frost-free days in Los Osos (a short growing season), running from the average last frost around January 19 to the first fall frost near January 14.
When should I plant tomatoes in Los Osos?
In Los Osos, start tomato seeds indoors around November 24–December 8, then transplant seedlings outdoors around January 26 once the danger of frost has passed.
Never miss a window in Los Osos
An email when it’s time to start seeds, transplant, and sow — timed to Los Osos’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reach- Morro Bay · 8 km
- San Luis Obispo · 15 km
- Atascadero · 23 km
- Grover Beach · 28 km
- Arroyo Grande · 30 km
- El Paso de Robles (Paso Robles) · 39 km
- Nipomo · 43 km
- Santa Maria · 54 km
Frost dates recorded at MORRO BAY FIRE DEPT, 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 Los Osos, CA — Frost Dates & Zone 10a." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USC00045866. Retrieved from https://blissgarden.com/california/los-osos.