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USDA hardiness zone lookup

Moscow (83843) — USDA Zone 6a

Moscow, Idaho · 131-day growing season

Frost dates and growing season for 83843

USDA hardiness zoneZone 6a
Average last spring frostMay 16
Average first fall frostSeptember 24
Growing season length~131 days
Temperature range (F)-10 to 0°F
Temperature range (C)-23 to -18°C

These are 50%-probability averages modeled from this ZIP'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 16, but in a colder-than-average year it 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 Moscow

Moscow, Idaho sits in USDA Zone 6a, with roughly 131 frost-free days between an average last spring frost around May 16 and a first fall frost around September 24. 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 Moscow

Moscow falls in USDA Zone 6a, which means the same hardiness constraints apply as the full Zone 6 guide. Vegetables, herbs, and fruit trees rated to Zone 6a (or hardier) will overwinter here in a typical year.

What to plant in Moscow this week

Moscow's last frost is around May 16. 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 Moscow

Crop-by-crop sowing, transplant, and harvest dates calibrated to zone 6 averages:

Local microclimate notes

Zone tables give you the average — but Moscowgardens 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) is more accurate than 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 this ZIP's USDA hardiness zone and regional NOAA 1991-2020 climate normals — they are zone-level estimates, not a per-station record, so treat them as planning guidance and confirm against your own local frost history. Crop recommendations are drawn from US Cooperative Extension references and curated by the Growli editorial team. Last reviewed May 2026.

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