Los Osos, CA frost dates
Frost is light and occasional here — typically a few cold nights around midwinter (about 3 a year). Cover tender plants when frost is forecast.
How Los Osos compares
- In a typical year, frost nights in Los Osos fall between January 14 and January 19. In 1 year in 10 the first frost comes as early as December 25, or the last frost as late as February 9.
- Compared with Santa Maria, CA, 55 km away, the last frost here is 16 days earlier than there.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | December 30 |
| 50% (median) | January 19 |
| 10% (safe for tender plants) | February 9 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | December 25 |
| 50% (median) | January 14 |
| 90% (late) | February 8 |
Frost here means 32°F (0°C). A median date means half of years have their last frost earlier and half later.
Gardening where frost is rare
Los Osos, CA only freezes on a few winter nights, so the usual "plant after the last frost" rule doesn't apply. Heat and rainfall decide the seasons instead:
- Cool-season crops (lettuce, broccoli, peas, carrots) grow best from fall through late winter.
- Warm-season crops (tomatoes, peppers, beans, squash) do best planted in late winter to spring, and again in late summer for a fall crop — midsummer heat can stop tomatoes setting fruit.
- Heat lovers (okra, sweet potatoes, melons) can be planted through spring and early summer.
About these dates
Based on 1991–2020 NOAA climate normals for the Morro Bay Fire Dept, CA weather station, 6 km away (elevation 118 ft (36 m)).
ZIP codes in Los Osos: 93402 93412
Frost dates near Los Osos
- Morro Bay Jan 19 · Jan 14
- Cayucos Jan 19 · Jan 14
- Avila Beach Feb 1 · Jan 4
- San Luis Obispo Jan 16 · Dec 25
- Atascadero Jan 19 · Jan 14
- Harmony Jan 19 · Jan 14
- Pismo Beach Feb 1 · Jan 4
- Grover Beach Feb 1 · Jan 4
- Templeton Mar 15 · Nov 10
- Oceano Feb 1 · Jan 4
Frequently asked questions
When is the last frost in Los Osos, CA?
The median last spring frost in Los Osos, CA is January 19. There is still about a 10% chance of frost after February 9, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Los Osos, CA?
The median first fall frost is January 14, with about a 10% chance of frost before December 25.
How long is the growing season in Los Osos, CA?
About 360 days between the median last spring frost and first fall frost.
What planting zone is Los Osos, CA?
Los Osos, CA is in USDA hardiness zone 10a.