First Frost 2026: When the Growing Season Ends, State by State

The frost line sweeps south for three months: high-elevation and northern-tier states (Alaska, Wyoming, North Dakota, Minnesota) typically see first frost in late August through September, the Midwest and Northeast in October, the South in November, and the Gulf Coast in December — if at all. Look up your state below or use the ZIP tool for your exact area.

Frost can form on surfaces with air temps as high as 36–37°F on calm, clear nights. A "freeze" is 32°F air temperature; a "hard freeze" is 28°F or below, which ends the growing season for nearly everything unprotected. The dates on this site are for the first 32°F freeze.

These are climatological medians — a 50% coin flip that frost has arrived by that date. They are the correct planning anchor, but any single autumn can run two weeks early or late. For day-precision, watch your NWS forecast once you're inside your window: frost advisories are issued 24–36 hours out.

Row covers or old sheets buy 2–6°F of protection (remove them in the morning); watering soil in the afternoon helps it hold daytime heat overnight; harvest tender crops ahead of any forecast below 35°F. Light frosts often precede weeks of good growing weather — one covered night can extend a garden a month.

Only the tender half. Basil, tomatoes, and peppers are done at 32°F — but kale, spinach, carrots, parsnips, and Brussels sprouts keep going into the 20s and teens, and actually sweeten as frost converts their starches to sugar. First frost is a handoff, not an ending.

Most first frosts are radiational: a clear, calm night lets the ground radiate its heat to space, chilling the surface below air temperature — that's why frost forms in valleys and on car roofs first, and why covering plants works. An advective freeze is a cold air mass moving in with wind; covers barely help, and everything tender ends at once. Early-season damage is nearly always the first kind.

No — they answer different questions. USDA zones rank average winter minimum temperature and tell you which perennials survive the year. Frost dates bracket the growing season and tell you when to plant annuals and vegetables. Two towns can share a zone but differ by weeks in frost dates; you need both numbers, and each state page here lists both.

On average, yes — the US growing season has lengthened by roughly two weeks over the past century, and the NOAA 1991–2020 normals used here already reflect part of that shift. But the year-to-year swing (±2 weeks) still dwarfs the trend, so plan on the median and watch the forecast rather than betting on a late frost.