What Grows in Round Rock, Arizona

The last hard freeze (28°F) in Round Rock typically lands around Apr 15, 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 6.

The first hard freeze (28°F) in Round Rock typically arrives around Oct 27, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 13, so the watching starts about Sep 27 — about 195 days after the spring freeze cleared.

Measured between 28°F hard freezes, Round Rock sees about 195 frost-free days — roughly Apr 15 through Oct 27, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 6 to Oct 13, about 160 days.

The federal record around Round Rock is light — 21 documented sites across the 9 federal source types we checked, mostly Nitrate entries (20), the nearest Nitrate record about 0.7 miles out — and proximity to a documented site is information, not a diagnosis of any one yard. Growing food here starts from a strong position; a soil test before new food beds settles any site-specific question.

From about Sep 27 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 27 (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 27. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.