First Frost Date by ZIP Code — Know Exactly When to Protect Your Garden

The first fall frost ends the growing season for most vegetables. Miss the warning and you'll wake up to blackened tomato plants, wilted basil, and squash vines that look like someone left them in the freezer. One night is all it takes.

Knowing your first expected frost date lets you plan harvests, protect tender plants, and save seeds before they're lost. Here's how to find your exact date — and what to do with it.

What "First Frost Date" Actually Means

Your first frost date is the median date when your area has a 50% chance of dropping to 32°F (0°C) or below. It's a statistical average based on decades of weather records from NOAA — not a guarantee.

Some years your first frost comes two weeks earlier than the median. Some years two weeks later. But the average gives you a reliable target for planning.

How to Find Your First Frost Date by ZIP Code

Several free tools give you location-specific frost date data:

• NOAA Climate Data: Search your nearest weather station at climate.gov for historical frost statistics
• Old Farmer's Almanac: almanac.com/gardening/frostdates — enter your ZIP code for spring and fall averages
• University Extension Services: State land-grant universities often publish county-level frost date tables with more local precision than national tools
• Cloche: Enter your ZIP during signup and Cloche automatically builds your planting calendar around your specific frost dates

The key is using a ZIP-level or county-level source, not just your USDA zone. Two properties in the same zone but different elevations or microclimates can have first frost dates two weeks apart.

First Frost Date Averages by Region

If you just need a ballpark, these regional averages are a solid starting point:

What to Do 2 Weeks Before Your First Frost

Once you have your date circled on the calendar, work backwards. Here's a practical two-week countdown:

2 Weeks Out

• Stop deadheading flowering plants — let them set seed
• Begin harvesting any mature tomatoes, peppers, eggplant, and summer squash
• Take cuttings of tender perennials you want to overwinter indoors (coleus, geraniums, begonias)
• Dig up any tubers or bulbs that aren't cold-hardy in your zone (dahlias, cannas, caladiums)

1 Week Out

• Harvest all green tomatoes — they'll ripen indoors on a counter (not a windowsill, oddly)
• Pull up basil entirely; it can't be saved once frost hits
• Pot up any herbs you want to bring indoors (rosemary, thyme)
• Gather frost cloth, old sheets, or row cover fabric — you'll use it soon

Day Before a Forecast Frost

• Water plants well — moist soil holds heat better than dry soil
• Cover tender plants with frost cloth, old bed sheets, or plastic (don't let plastic touch leaves)
• Move containers indoors or into a garage
• Leave covers on until mid-morning the next day — frost can continue into early morning even after sunrise

Plants That Survive Frost (Don't Rush to Pull These)

Not everything needs to come in before the freeze. These crops are frost-hardy and often taste better after a light freeze, which converts starches to sugars:

• Kale — survives down to 10°F with protection, improves with frost
• Brussels sprouts — flavor peak is post-frost
• Carrots — can be left in ground until hard freeze, sweetens with cold
• Parsnips — same as carrots; often left in ground all winter in Zones 5+
• Spinach — handles light frost easily, even light freeze with protection
• Garlic — planted in fall specifically to overwinter
• Leeks — one of the hardiest alliums

What Kills Immediately at First Frost

These are your priorities to harvest or protect at the first sign of a forecast:

• Tomatoes, peppers, eggplant
• Basil, cilantro, most herbs (except rosemary, thyme, sage in warmer zones)
• Cucumbers, summer squash, zucchini
• Beans (green, pole, bush)
• Sweet corn
• Winter squash and pumpkins (the fruit is fine post-frost if the vine dies; harvest immediately)

Track Your Frost Dates Automatically

The easiest way to never get caught off guard is to have a garden app that already knows your frost dates. Cloche shows your upcoming frost window based on your ZIP code, sends reminders before expected frost events, and adjusts your entire care schedule around your seasonal boundaries automatically.

You don't need to look up dates or do the math — it's all built into your garden's living calendar.