Frost Dates: First and last frost dates for Mormon Flat, AZ
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 April 28, you have a 90% chance of being frost-free — this is your "safe date" for planting tender crops
- Around March 29, there's a 50/50 chance of frost — check weather forecasts carefully if planting now
- Before March 9, 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° | Dec 30 | -- | -- | -- | -- | -- | -- | -- | -- |
| Last 20° | Jan 17 | Dec 28 | -- | -- | -- | -- | -- | -- | -- |
| Last 24° | Feb 5 | Jan 23 | Jan 12 | Dec 30 | Dec 10 | -- | -- | -- | -- |
| Last 28° | Mar 6 | Feb 20 | Feb 10 | Feb 2 | Jan 24 | Jan 16 | Jan 6 | Dec 23 | -- |
| Last 32° | Apr 5 | Mar 26 | Mar 18 | Mar 12 | Mar 6 | Mar 1 | Feb 22 | Feb 15 | Feb 5 |
| Last 36° | Apr 28 | Apr 18 | Apr 10 | Apr 4 | Mar 29 | Mar 23 | Mar 17 | Mar 9 | Feb 27 |
ℹ️ How to read these charts for the fall
As summer ends in Mormon Flat, AZ, 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° | Dec 29 | Jan 28 | -- | -- | -- | -- | -- | -- | -- |
| First 24° | Dec 8 | Dec 24 | Jan 7 | Jan 24 | -- | -- | -- | -- | -- |
| First 28° | Nov 17 | Nov 27 | Dec 4 | Dec 10 | Dec 16 | Dec 22 | Dec 30 | Jan 11 | -- |
| First 32° | Nov 12 | Nov 17 | Nov 20 | Nov 24 | Nov 26 | Nov 29 | Dec 2 | Dec 6 | Dec 11 |
| First 36° | Oct 31 | Nov 5 | Nov 9 | Nov 12 | Nov 15 | Nov 18 | Nov 21 | Nov 25 | Nov 30 |
📍 Frost Dates for other nearby locations
- Needles Ap, CA 43.8 mi
- Searchlight, NV 47.6 mi
- Willow Beach, AZ 49.0 mi
- Wikieup, AZ 60.0 mi
- Boulder City, NV 62.9 mi
- Parker Rsvr, CA 69.2 mi
- Parker, AZ 78.4 mi
- Las Vegas, NV 82.9 mi
- Bagdad, AZ 88.9 mi
- Mtn Pass, CA 89.9 mi
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Data is provided by the NOAA National Centers for Environmental Information.