USDA hardiness zone lookup
Seattle (Columbia City) (98118) — USDA Zone 9a
Seattle (Columbia City), Washington · 248-day growing season
Frost dates and growing season for 98118
| USDA hardiness zone | Zone 9a |
|---|---|
| Average last spring frost | March 14 |
| Average first fall frost | November 17 |
| Growing season length | ~248 days |
| Temperature range (F) | 20 to 30°F |
| Temperature range (C) | -7 to -1°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 March 14, 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 Seattle (Columbia City)
Seattle (Columbia City), Washington sits in USDA Zone 9a, with roughly 248 frost-free days between an average last spring frost around March 14 and a first fall frost around November 17. That is a near year-round season — the limiting factor is summer heat, not frost, so schedule cool-season crops for winter and protect tender ones from extreme highs.
What grows in Seattle (Columbia City)
Seattle (Columbia City) falls in USDA Zone 9a, which means the same hardiness constraints apply as the full Zone 9 guide. Vegetables, herbs, and fruit trees rated to Zone 9a (or hardier) will overwinter here in a typical year.
- Tomatoes (year-round in many areas)
- Peppers (all year)
- Citrus (oranges, lemons, limes, grapefruit)
- Avocado
- Mango (warmer areas)
- Banana
- Sweet potatoes
- Okra
- Southern peas
- Pomegranates
What to plant in Seattle (Columbia City) this week
Seattle (Columbia City) is in the winter hold — outdoor planting is on pause. Use this time to plan, order seeds, and prep beds. Tomato and pepper seeds can start indoors 6-10 weeks before your last frost (March 14).
- When to plant tomatoes in zone 9
- When to plant peppers in zone 9
- When to plant basil in zone 9
- When to plant lettuce in zone 9
- When to plant peas in zone 9
Full planting calendar for Seattle (Columbia City)
Crop-by-crop sowing, transplant, and harvest dates calibrated to zone 9 averages:
- When to plant tomatoes in zone 9
- When to plant peppers in zone 9
- When to plant basil in zone 9
- When to plant garlic in zone 9
- When to plant lettuce in zone 9
- When to plant bush beans in zone 9
- When to plant cucumbers in zone 9
- When to plant summer squash in zone 9
- When to plant peas in zone 9
- When to plant carrots in zone 9
Local microclimate notes
Zone tables give you the average — but Seattle (Columbia City)gardens 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.
Nearby ZIP codes in Washington
- 98101 — Seattle (Zone 9a)
- 98109 — Seattle (Queen Anne) (Zone 9a)
- 98103 — Seattle (Fremont) (Zone 8b)
- 98501 — Olympia (Zone 8b)
- 98401 — Tacoma (Zone 8b)
- 98201 — Everett (Zone 8b)
- 98225 — Bellingham (Zone 8b)
- 99201 — Spokane (Zone 7a)
- 98660 — Vancouver (Zone 8b)
- 98801 — Wenatchee (Zone 6b)
- 98105 — Seattle (University District) (Zone 9a)
- 98115 — Seattle (Wedgwood) (Zone 9a)
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