Frost Dates: First and last frost dates for San Jose, CA
ℹ️ How to read these charts for the spring
As spring unfolds, the risk of frost gradually decreases each day until your tender plants are finally safe. The probabilities shown in the chart help you make smart decisions about when to plant.
While frost typically forms at 32°F, tender plants can be damaged even when temperatures are slightly higher. Air temperatures are often measured several feet above the ground, but temperatures at plant level can be several degrees colder. Protected areas like porches help by blocking radiational cooling. Given these variables, we consider 36°F the "caution zone" for frost-sensitive plants.
Key dates for your spring planting:
- By March 17, you have a 90% chance of being frost-free — this is your "safe date" for planting tender crops
- Around February 13, there's a 50/50 chance of frost — check weather forecasts carefully if planting now
- Before January 23, there's still an 80% risk of frost — too early for tomatoes and other tender plants unless you're prepared to protect them
If the 10-day forecast shows no temperatures below 40°F, you might safely plant earlier than the above dates suggest. Many gardeners watch for this weather window to get a head start on the growing season.
| Temperature | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| Last 16° | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| Last 20° | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| Last 24° | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| Last 28° | Jan 16 | Dec 30 | Dec 7 | -- | -- | -- | -- | -- | -- |
| Last 32° | Feb 10 | Feb 1 | Jan 24 | Jan 18 | Jan 11 | Jan 4 | Dec 27 | Dec 11 | -- |
| Last 36° | Mar 17 | Mar 6 | Feb 26 | Feb 19 | Feb 13 | Feb 7 | Jan 31 | Jan 23 | Jan 12 |
ℹ️ How to read these charts for the fall
As summer ends in San Jose, CA, nighttime temperatures begin to drop, and your risk of frost increases with each passing day. Knowing when to expect frost helps you harvest sensitive crops and extend your growing season with protection methods.
The chart below shows the probability of experiencing specific temperatures on various dates. Here's what this means for your garden:
These probabilities help you time your end-of-season harvests and know when to apply protective measures like row covers, cloches, or cold frames to extend your harvest.
| Temperature | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| First 16° | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| First 20° | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| First 24° | -- | -- | -- | -- | -- | -- | -- | -- | -- |
| First 28° | Dec 14 | Dec 30 | Jan 20 | -- | -- | -- | -- | -- | -- |
| First 32° | Nov 24 | Dec 5 | Dec 12 | Dec 19 | Dec 26 | Jan 2 | Jan 11 | Jan 28 | -- |
| First 36° | Oct 31 | Nov 10 | Nov 17 | Nov 23 | Nov 29 | Dec 4 | Dec 10 | Dec 17 | Dec 27 |
📍 Frost Dates for other nearby locations
- Los Gatos, CA 8.3 mi
- Newark, CA 15.5 mi
- Mt Hamilton, CA 17.7 mi
- Palo Alto, CA 18.3 mi
- Santa Cruz, CA 24.7 mi
- Redwood City, CA 25.5 mi
- Livermore, CA 26.3 mi
- Watsonville Wtr Wks, CA 29.4 mi
- San Gregorio, CA 32.1 mi
- Gilroy, CA 32.8 mi
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Data is provided by the NOAA National Centers for Environmental Information.