When to plant in Smithfield, UT
USDA Zone 6aHere are the average frost dates, USDA hardiness zone, and a month-by-month planting calendar for Smithfield, Utah — all computed from Smithfield's nearest NOAA weather station.
In zone 6a, Smithfield gardeners can grow many hardy perennials, while the last and first frost still dictate the annual vegetable calendar.
The average last spring frost in Smithfield is now 14 days earlier than in the 1981–2010 normals. See how frost dates are shifting nationwide →
Frost probability
LOGAN CACHE 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 Smithfield’s own odds, recorded at LOGAN CACHE AP.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | Jun 17 | May 30 | May 10 | Sep 5 | Sep 20 | Oct 4 |
| 32°F | May 29 | May 8 | Apr 24 | Sep 19 | Oct 2 | Oct 15 |
| 28°F | May 6 | Apr 22 | Apr 4 | Sep 29 | Oct 13 | Oct 27 |
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 Smithfield, 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.
Smithfield planting FAQ
When is the last spring frost in Smithfield, UT?
Plan for the last spring frost in Smithfield around May 8 (the date it has a 50% chance of a 32°F freeze). Anything frost-sensitive should go out after it.
When is the first fall frost in Smithfield, UT?
In Smithfield, the first 32°F freeze of fall lands around October 2 on average. Time your last harvests and any season-extension cover before it.
What hardiness zone is Smithfield in?
Smithfield is in USDA hardiness zone 6a. In zone 6a, winters are moderate — most common vegetables grow well in season.
How long is the growing season in Smithfield?
Smithfield has about 147 frost-free days — a short growing season — between the average last spring frost (May 8) and first fall frost (October 2).
When should I plant tomatoes in Smithfield?
For Smithfield, sow tomatoes indoors about March 13–March 27 and move the seedlings out around May 15, after the last spring frost.
Never miss a window in Smithfield
An email when it’s time to start seeds, transplant, and sow — timed to Smithfield’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reach- North Logan · 7 km
- Logan · 11 km
- Hyrum · 23 km
- Tremonton · 33 km
- Brigham City · 41 km
- Pleasant View · 59 km
- North Ogden · 59 km
- Ogden · 69 km
Frost dates recorded at LOGAN CACHE AP, 6 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 Smithfield, UT — Frost Dates & Zone 6a." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USW00094128. Retrieved from https://blissgarden.com/utah/smithfield.