When to plant in Washington, UT
USDA Zone 8bHere are the average frost dates, USDA hardiness zone, and a month-by-month planting calendar for Washington, Utah — all computed from Washington's nearest NOAA weather station.
With about 241 frost-free days, Washington supports back-to-back plantings; stagger sowings every few weeks to keep beds productive spring through fall. Zone 8b means many perennials and even some tender shrubs overwinter in Washington, while your frost dates still decide when annuals go out.
The average last spring frost in Washington is now 7 days later than in the 1981–2010 normals. See how frost dates are shifting nationwide →
Frost probability
ST GEORGE · 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 Washington’s own odds, recorded at ST GEORGE.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | Apr 21 | Apr 3 | Mar 17 | Oct 19 | Nov 1 | Nov 12 |
| 32°F | Apr 6 | Mar 14 | Feb 27 | Oct 27 | Nov 10 | Nov 22 |
| 28°F | Mar 17 | Feb 27 | Feb 7 | Nov 7 | Nov 20 | Dec 3 |
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 Washington, drawn to the day from the local frost dates. The dashed line is today.
Nearby weather stations
3 within 30 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.
Washington planting FAQ
When is the last spring frost in Washington, UT?
Washington's average last spring frost falls near March 14 — the 50% mark at 32°F in the 1991–2020 normals. Hold tender transplants until the risk has passed, then plant out.
When is the first fall frost in Washington, UT?
Expect Washington's first fall frost near November 10 — a 50% chance of 32°F by that date. Bring in or cover tender crops ahead of it.
What hardiness zone is Washington in?
Washington is in USDA hardiness zone 8b. In zone 8b, winters are mild — many tender perennials overwinter here.
How long is the growing season in Washington?
There are roughly 241 frost-free days in Washington (a long growing season), running from the average last frost around March 14 to the first fall frost near November 10.
When should I plant tomatoes in Washington?
In Washington, start tomato seeds indoors around January 17–January 31, then transplant seedlings outdoors around March 21 once the danger of frost has passed.
Never miss a window in Washington
An email when it’s time to start seeds, transplant, and sow — timed to Washington’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reach- St. George · 10 km
- Hurricane · 12 km
- Mesquite · 67 km
- Cedar City · 71 km
- North Las Vegas · 170 km
- Sunrise Manor · 175 km
- Whitney · 179 km
- Winchester · 184 km
Frost dates recorded at ST GEORGE, 11 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 Washington, UT — Frost Dates & Zone 8b." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USC00427516. Retrieved from https://blissgarden.com/utah/washington.