Frost Dates
Utah Frost Dates
A frost date is the average date of the last light freeze in spring or the first light freeze in fall. Knowing your frost dates helps you determine the best time to plant, transplant, and protect your garden throughout the growing season.
What Are Frost Dates?
A frost date is the average date of the last light freeze in spring or the first light freeze in fall.
The classification of freeze temperatures is based on their effect on plants:
- Light Freeze: 29° to 32°F (-1.7° to 0°C) — tender plants are killed.
- Moderate Freeze: 25° to 28°F (-3.9° to -2.2°C) — widely destructive to most vegetation.
- Severe Freeze: 24°F (-4.4°C) and colder — heavy damage to most garden plants.
Frost dates are estimates based on historical weather data. Actual frost dates can vary from year to year, sometimes by several days or even weeks.
Use the resources below to find approximate frost dates for your area by entering your ZIP code.
Frost Date Resources
Why Frost Dates Matter
Planting too early can expose young plants to damaging cold temperatures. Planting too late can shorten your growing season and reduce harvests.
Frost dates are especially helpful for:
- Starting seeds indoors
- Transplanting vegetables and flowers outdoors
- Planting warm-season crops such as tomatoes, peppers, squash, cucumbers, melons, and basil
- Protecting tender plants during cold weather
- Planning succession planting and fall gardens
Frost Dates Are Averages
Frost dates are based on historical weather averages and should be used as guidelines, not guarantees.
Because weather changes from year to year, it is wise to assume freezing temperatures remain possible approximately two weeks before the first fall frost date and two weeks after the last spring frost date.
Utah Microclimates
Utah’s diverse elevations, mountains, valleys, and urban areas create numerous microclimates. Frost dates may vary significantly even within the same city.
Low spots often collect cold air and frost sooner. South-facing walls, protected courtyards, raised beds, and areas near pavement often remain warmer.
Understanding your own yard’s unique conditions can be just as important as knowing the official frost dates.
Tips for Gardening Around Frost Dates
- Check local frost dates before planting.
- Watch weather forecasts closely in spring and fall.
- Keep frost cloth, sheets, row covers, or buckets available for protection.
- Harden off seedlings before planting outdoors.
- Plant cool-season crops earlier and warm-season crops after frost danger has passed.
- Use mulch to help insulate soil and roots.
Cool-Season vs. Warm-Season Crops
Cool-season crops tolerate cooler temperatures and are often planted before the last frost. Examples include:
- Lettuce
- Spinach
- Peas
- Radishes
- Kale
- Broccoli
- Cabbage
- Carrots
- Onions
- Potatoes
Warm-season crops are sensitive to frost and should be planted after frost danger has passed. Examples include:
- Tomatoes
- Peppers
- Cucumbers
- Squash
- Beans
- Basil
- Corn
- Melons
- Pumpkins
Final Thought
Frost dates are one of the most valuable planning tools available to gardeners. Use them as a guide, but combine them with local weather forecasts, your garden’s microclimate, and your own observations.
The better you understand your local conditions, the more successful your garden will be throughout the growing season.