First and Last Frost Dates by Zip Code 2026 for Places in Utah

Select a City in UT

What Are Frost Dates?

Use our 2026 Frost Dates Calculator to find the average date of the last spring frost and first fall frost in your area—based on data from the nearest official weather station and your ZIP or Postal Code. These dates estimate your growing season length and help you plan planting, harvesting, and garden care.

Your last spring frost date marks when it’s generally safe to plant outdoors. Your first fall frost date signals the end of the growing season for warm-weather crops.

👉 New for 2026: See our Last Frost Date Map for THIS season.

What Is a Last Spring Frost Date?

Your last spring frost is the average final date when temperatures may dip to 32°F (0°C). After this point, the risk of frost decreases—but frost is still possible, so always monitor your local weather forecast.

These dates are based on historical climate data using a 30% probability threshold, meaning there is still a chance of frost after the listed date.

Why Spring Frost Dates Matter

Knowing your last frost date helps you:

Start seeds indoors at the right time
Transplant seedlings safely outdoors
Avoid cold damage to tender vegetables, herbs, and flowers
Timing your planting around frost dates increases success—especially for crops like:
- Tomatoes
- Peppers
- Cucumbers
- Basil
- Zinnias and marigolds

See Our Planting Calendar by ZIP Code

What Can I Plant Before the Last Frost?

Some hardy crops tolerate light frost and can be planted before your last frost date:

Peas
Spinach
Radishes
Carrots
Onions
Lettuce

What Is the Growing Season?

The time between your last spring frost and first fall frost is your growing season—the window when most warm-weather plants can thrive.

Knowing this helps you:

Choose appropriate crop varieties (based on "days to maturity")
Plan succession plantings for longer harvests
Time both spring and fall crops with confidence

Learn How to Extend the Growing Season.

Spring Frost Date FAQs

Can frost happen after my last spring frost date?
Yes. Frost dates are averages. Always check your local forecast before planting warm-season crops outdoors.

What should I plant first?
Hardy vegetables like spinach, peas, and carrots can go in before the last frost. Tender crops like tomatoes and basil must wait until all danger of frost has passed.

Should I start seeds indoors before the frost date?
Yes. Use your last frost date to count backward and determine when to start seeds indoors.

What temperature counts as a frost?
32°F (0°C) is considered a light frost. Some plants may be damaged in the 33°F–36°F range, depending on conditions.