When to plant in Renton, WA
USDA Zone 9aHere are the average frost dates, USDA hardiness zone, and a month-by-month planting calendar for Renton, Washington — all computed from Renton's nearest NOAA weather station.
A generous ~248-day season lets Renton gardeners direct-sow more and still ripen long-maturity crops like melons and winter squash. In zone 9a, frost is a minor factor for Renton — most perennials thrive, and annual vegetables can go out early and stay late.
Frost probability
RENTON MUNI AP · 1991–2020The date the last spring and first fall frost occur, by threshold and probability. A 90% date is later in spring — and earlier in fall — than a 10% date; the 50% · 32°F row is what most gardeners plan around. These are Renton’s own odds, recorded at RENTON MUNI AP.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | Apr 25 | Apr 6 | Mar 21 | Oct 17 | Oct 31 | Nov 17 |
| 32°F | Mar 31 | Mar 13 | Feb 19 | Oct 29 | Nov 16 | Dec 9 |
| 28°F | Mar 6 | Feb 13 | Jan 1 | Nov 11 | Dec 6 | Jan 9 |
Download this table as CSV ↓ — every threshold and probability, plus this city’s planting-window dates.
What to plant now
TODAY · JULY 19Full-year planting calendar
Each bar is the exact window to take a planting action in Renton, drawn to the day from the local frost dates. The dashed line is today.
Nearby weather stations
3 within 10 km · complete 32°F normalsWhen stations disagree by more than a few days, that spread is real microclimate variation — elevation, water, urban heat. Judge which station best matches your own yard.
Renton planting FAQ
When is the last spring frost in Renton, WA?
On average, the last spring frost in Renton is around March 13 (50% probability at 32°F, from 1991–2020 NOAA normals). Wait until after this date to set out tender plants like tomatoes and peppers.
When is the first fall frost in Renton, WA?
Expect Renton's first fall frost near November 16 — a 50% chance of 32°F by that date. Bring in or cover tender crops ahead of it.
What hardiness zone is Renton in?
Renton is in USDA hardiness zone 9a. In zone 9a, winters are mild — many tender perennials overwinter here.
How long is the growing season in Renton?
Renton has about 248 frost-free days — a long growing season — between the average last spring frost (March 13) and first fall frost (November 16).
When should I plant tomatoes in Renton?
For Renton, sow tomatoes indoors about January 16–January 30 and move the seedlings out around March 20, after the last spring frost.
Never miss a window in Renton
An email when it’s time to start seeds, transplant, and sow — timed to Renton’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reach- Bryn Mawr-Skyway · 4 km
- Fairwood · 5 km
- Tukwila · 6 km
- Newcastle · 6 km
- East Renton Highlands · 8 km
- SeaTac · 9 km
- Mercer Island · 10 km
- Kent · 10 km
Frost dates recorded at RENTON MUNI AP, 2 km from the city center · 1991–2020 NOAA climate normals · zone from the USDA/PRISM 2023 map. How we compute this.
BlissGarden. "When to Plant in Renton, WA — Frost Dates & Zone 9a." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USW00094248. Retrieved from https://blissgarden.com/washington/renton.