🍂 2026 First Frost Dates for Cortez, Colorado 81321
The first 36°F frost date is 30% likely to be on Sep 14. (See detailed probabilities below.)
The first 32°F light freeze date is 30% likely to be on Sep 23. (See detailed probabilities below.)
(See also 🌷 Last Spring Frost Dates.)
First frost date probabilities for Cortez, CO are based on historical climate data.
Always check your local forecast for the most up-to-date frost warnings.
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What is a First Frost Date?
The first fall frost signals the end of your local growing season. This date serves as an important deadline for gardeners and farmers. You'll need to complete harvesting before this point. Annuals and other tender plants will die back when frost hits, and perennial plants will enter their dormant phase for winter. Meanwhile, it's time to enjoy a cup of hot cocoa and a cozy sweater—and start planning your spring garden!
How to use the First Frost Date?
Watch your local weather forecasts in early fall to predict the first frost date. Harvest tender crops and protect vulnerable plants before frost arrives. For late-summer plantings, count backward from your area's average first frost date. This ensures your crops have enough time to mature. Keep track of when frost actually occurs in your garden each year. This helps you identify protected spots where the growing season might last longer.
First Frost Date Probabilities
| Probability of frost (36°F) on or before... | |
|---|---|
| 10% chance | Sep 8 |
| 20% chance | Sep 12 |
| 30% chance | Sep 14 |
| 40% chance | Sep 17 |
| 50% chance | Sep 20 |
| 60% chance | Sep 22 |
| 70% chance | Sep 24 |
| 80% chance | Sep 26 |
| 90% chance | Sep 30 |
| Probability of light freeze (32°F) on or before... | |
|---|---|
| 10% chance | Sep 17 |
| 20% chance | Sep 21 |
| 30% chance | Sep 23 |
| 40% chance | Sep 26 |
| 50% chance | Sep 28 |
| 60% chance | Oct 1 |
| 70% chance | Oct 3 |
| 80% chance | Oct 5 |
| 90% chance | Oct 10 |
| Probability of moderate freeze (28°F) on or before... | |
|---|---|
| 10% chance | Sep 26 |
| 20% chance | Sep 30 |
| 30% chance | Oct 3 |
| 40% chance | Oct 5 |
| 50% chance | Oct 7 |
| 60% chance | Oct 10 |
| 70% chance | Oct 13 |
| 80% chance | Oct 16 |
| 90% chance | Oct 21 |
| Probability of moderate hard freeze (24°F) on or before... | |
|---|---|
| 10% chance | Oct 4 |
| 20% chance | Oct 8 |
| 30% chance | Oct 11 |
| 40% chance | Oct 14 |
| 50% chance | Oct 17 |
| 60% chance | Oct 20 |
| 70% chance | Oct 23 |
| 80% chance | Oct 27 |
| 90% chance | Nov 1 |
| Probability of hard freeze (20°F) on or before... | |
|---|---|
| 10% chance | Oct 13 |
| 20% chance | Oct 18 |
| 30% chance | Oct 21 |
| 40% chance | Oct 24 |
| 50% chance | Oct 28 |
| 60% chance | Oct 31 |
| 70% chance | Nov 3 |
| 80% chance | Nov 6 |
| 90% chance | Nov 12 |
| Probability of severe hard freeze (16°F) on or before... | |
|---|---|
| 10% chance | Oct 22 |
| 20% chance | Oct 28 |
| 30% chance | Nov 1 |
| 40% chance | Nov 5 |
| 50% chance | Nov 8 |
| 60% chance | Nov 11 |
| 70% chance | Nov 15 |
| 80% chance | Nov 19 |
| 90% chance | Nov 23 |
Agricultural climatic data from weather station: CORTEZ MONTEZUMA CO AP (USW00093069:frost)