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USDA hardiness zone lookup

Brookings, SD — USDA Zone 4b

Brookings, South Dakota · 140-day growing season

Frost dates and growing season in Brookings

USDA hardiness zoneZone 4b
Average last spring frostMay 10
Average first fall frostSeptember 27
Growing season length~140 days
Temperature range (F)-30 to -20°F
Temperature range (C)-34 to -29°C

All of Brookings's mapped ZIP codes fall in the same hardiness band, Zone 4b.

These are 50%-probability averages modeled from Brookings's USDA hardiness zone and regional climate normals — not a single-station reading. In a typical year the last spring frost will have passed by May 10, but a colder-than-average year can run 1-2 weeks later. Plant tender crops (tomatoes, peppers, basil) once both soil and night temperatures are consistently warm — a thermometer beats the calendar.

Growing season in Brookings

Brookings, South Dakota sits in USDA Zone 4b, with roughly 140 frost-free days between an average last spring frost around May 10 and a first fall frost around September 27. That is a standard temperate season — most common vegetables finish comfortably, and a single main planting plus one succession round works well.

What grows in Brookings

Brookings falls in USDA Zone 4b, so the same hardiness constraints apply as the full Zone 4 guide. Vegetables, herbs, and fruit trees rated to Zone 4b (or hardier) will overwinter here in a typical year.

What to plant in Brookings this week

Brookings's last frost is around May 10. This is the spring transplant window — start tomatoes and peppers indoors if you haven't, and direct-sow cold-tolerant crops now.

Full planting calendar for Brookings

Crop-by-crop sowing, transplant, and harvest dates calibrated to zone 4 averages:

ZIP codes in Brookings

Drill down to the precise frost window and planting calendar for a specific ZIP in Brookings:

Local microclimate notes

Zone tables give you the average — but Brookingsgardens vary. South-facing walls and paved areas can run a full half-zone warmer than the published rating. Low-lying spots, frost pockets, and shaded north sides can run colder. If you've gardened here a few seasons, your own frost record — the last time you actually got frost damage — beats any national average.

Source and methodology

Hardiness zone from the USDA Plant Hardiness Zone Map (2023 revision). Frost-date and growing-season figures are modeled from Brookings's USDA hardiness zone and regional NOAA 1991-2020 climate normals — zone-level estimates, not a per-station record, so treat them as planning guidance and confirm against your own local frost history. Crop recommendations draw on US Cooperative Extension references, curated by the Growli editorial team. Last reviewed June 2026.

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