What Grows in Eau Claire, Wisconsin

The last hard freeze (28°F) in Eau Claire typically lands around Apr 22, per NOAA 1991–2020 climate normals — earlier than the light-frost dates most charts quote. That marks the hard freeze, not the last light frost — lighter frosts keep biting past it, which is why tender transplants here wait until about May 13.

The first hard freeze (28°F) in Eau Claire typically arrives around Oct 16, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 2, so the watching starts about Sep 16 — about 177 days after the spring freeze cleared.

Measured between 28°F hard freezes, Eau Claire sees about 177 frost-free days — roughly Apr 22 through Oct 16, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 13 to Oct 2, about 142 days.

The federal record around Eau Claire runs heavier than most — 1,022 documented sites, mostly Underground Storage Tanks entries (558), the nearest Underground Storage Tanks record about 0.1 miles out — so test the soil before planting food in the ground, and raised beds with clean imported soil grow well in the meantime. Even here, proximity to a documented site is information, not a diagnosis of any one yard; the contamination map shows exactly what's recorded and where.

From about Sep 16 the job here turns from planting to protecting — the last start even a 30-day crop can finish. As the season closes around the first 28°F hard freeze near Oct 16 (NOAA 1991–2020 climate normals), three moves buy time: row cover or an old sheet over tender plants on still, clear nights; water the soil the afternoon before a freeze, so it holds warmth overnight; and harvest tomatoes, peppers and basil before Oct 16. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.