Frost Dates: First and last frost dates for Downieville, 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 June 22, you have a 90% chance of being frost-free — this is your "safe date" for planting tender crops
- Around June 3, there's a 50/50 chance of frost — check weather forecasts carefully if planting now
- Before May 21, 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° | Feb 6 | Jan 23 | Jan 11 | Dec 26 | -- | -- | -- | -- | -- |
| Last 20° | Mar 15 | Feb 25 | Feb 12 | Jan 31 | Jan 20 | Jan 7 | Dec 23 | Nov 24 | -- |
| Last 24° | Apr 6 | Mar 24 | Mar 15 | Mar 6 | Feb 27 | Feb 19 | Feb 11 | Feb 2 | Jan 20 |
| Last 28° | May 5 | Apr 27 | Apr 21 | Apr 16 | Apr 11 | Apr 6 | Apr 1 | Mar 26 | Mar 17 |
| Last 32° | Jun 2 | May 26 | May 21 | May 17 | May 12 | May 8 | May 4 | Apr 29 | Apr 21 |
| Last 36° | Jun 22 | Jun 15 | Jun 10 | Jun 6 | Jun 3 | May 30 | May 26 | May 21 | May 15 |
ℹ️ How to read these charts for the fall
As summer ends in Downieville, 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 11 | Dec 24 | Jan 5 | Jan 23 | -- | -- | -- | -- | -- |
| First 20° | Nov 4 | Nov 19 | Nov 30 | Dec 10 | Dec 20 | Jan 1 | Jan 16 | -- | -- |
| First 24° | Nov 1 | Nov 10 | Nov 17 | Nov 22 | Nov 28 | Dec 3 | Dec 8 | Dec 15 | Dec 24 |
| First 28° | Oct 24 | Oct 29 | Nov 1 | Nov 3 | Nov 6 | Nov 8 | Nov 11 | Nov 14 | Nov 18 |
| First 32° | Sep 29 | Oct 6 | Oct 10 | Oct 15 | Oct 18 | Oct 22 | Oct 26 | Oct 31 | Nov 7 |
| First 36° | Sep 13 | Sep 19 | Sep 24 | Sep 27 | Oct 1 | Oct 4 | Oct 8 | Oct 12 | Oct 18 |
📍 Frost Dates for other nearby locations
- Bowman Dam, CA 14.9 mi
- Sierra City, CA 14.9 mi
- Strawberry Valley, CA 18.6 mi
- Blue Canyon Nyack Ap, CA 21.9 mi
- Lake Spaulding, CA 22.1 mi
- Nevada City, CA 24.9 mi
- Quincy, CA 26.7 mi
- Dobbins, CA 29.0 mi
- Grass Valley #2, CA 29.7 mi
- Portola, CA 30.3 mi
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Data is provided by the NOAA National Centers for Environmental Information.