Frost Dates: First and last frost dates for Willits, 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 July 2, you have a 90% chance of being frost-free — this is your "safe date" for planting tender crops
- Around June 13, there's a 50/50 chance of frost — check weather forecasts carefully if planting now
- Before May 31, 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° | Jan 27 | Jan 4 | Dec 4 | -- | -- | -- | -- | -- | -- |
| Last 20° | Feb 8 | Jan 25 | Jan 15 | Jan 6 | Dec 28 | Dec 17 | Nov 30 | -- | -- |
| Last 24° | Mar 16 | Mar 1 | Feb 18 | Feb 9 | Jan 31 | Jan 22 | Jan 12 | Dec 31 | Dec 13 |
| Last 28° | May 10 | Apr 26 | Apr 17 | Apr 9 | Apr 1 | Mar 24 | Mar 16 | Mar 6 | Feb 21 |
| Last 32° | Jun 5 | May 27 | May 21 | May 16 | May 11 | May 6 | May 1 | Apr 25 | Apr 16 |
| Last 36° | Jul 2 | Jun 26 | Jun 21 | Jun 17 | Jun 13 | Jun 9 | Jun 5 | May 31 | May 25 |
ℹ️ How to read these charts for the fall
As summer ends in Willits, 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° | Dec 14 | Jan 10 | Feb 15 | -- | -- | -- | -- | -- | -- |
| First 20° | Nov 15 | Nov 28 | Dec 8 | Dec 17 | Dec 26 | Jan 5 | Jan 21 | -- | -- |
| First 24° | Oct 28 | Nov 8 | Nov 16 | Nov 23 | Nov 29 | Dec 6 | Dec 13 | Dec 22 | Jan 4 |
| First 28° | Oct 4 | Oct 14 | Oct 21 | Oct 27 | Nov 1 | Nov 7 | Nov 13 | Nov 20 | Nov 30 |
| First 32° | Sep 21 | Sep 27 | Oct 2 | Oct 6 | Oct 9 | Oct 13 | Oct 17 | Oct 21 | Oct 28 |
| First 36° | Aug 19 | Aug 29 | Sep 5 | Sep 11 | Sep 17 | Sep 22 | Sep 28 | Oct 5 | Oct 15 |
📍 Frost Dates for other nearby locations
- Potter Valley P H, CA 18.0 mi
- Ukiah, CA 23.9 mi
- Covelo, CA 26.7 mi
- Ft Bragg, CA 26.9 mi
- Lakeport, CA 42.8 mi
- Richardson Gr Sp, CA 49.3 mi
- Cloverdale, CA 51.4 mi
- Stony Gorge Rsvr, CA 58.8 mi
- East Park Rsvr, CA 59.5 mi
- Ft Ross, CA 65.4 mi
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Data is provided by the NOAA National Centers for Environmental Information.