Smithfield, UT frost dates
Last spring frostMay 8median date
First fall frostOct 2median date
Growing season147 daysfrost-free
Hardiness zone6aZone 6a
How Smithfield compares
- In 8 years out of 10, the last spring frost in Smithfield falls between April 24 and May 29, a 35-day window. The first fall frost falls between September 19 and October 15.
- The median last frost is 2 days earlier than the Utah median of May 10.
- Its 147-day growing season is longer than 48% of the 250 Utah places with a regular frost season (state median 148 days).
- The last frost is 9 days later than the zone 6a median of Apr 29. Hardiness zones measure winter cold, not season length, so use these dates rather than a zone 6a chart.
- The weather station records an average of 173 nights a year at or below 32°F.
- Compared with Logan, UT, 13 km away, the last frost here is the same as there and the growing season is the same length.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | April 24 |
| 50% (median) | May 8 |
| 10% (safe for tender plants) | May 29 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | September 19 |
| 50% (median) | October 2 |
| 90% (late) | October 15 |
Frost here means 32°F (0°C). A median date means half of years have their last frost earlier and half later.
Planting calendar for Smithfield, UT
Smithfield, UT frost dates — last frost May 8, first frost Oct 2, zone 6a. whenisthelastfrost.com
Crop
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Start indoors: Feb 13 to Feb 27Transplant outside: Apr 10 to Apr 24
Start indoors: Feb 27 to Mar 13Transplant outside: May 22 to Jun 5
Start indoors: Feb 27 to Mar 13Transplant outside: May 22 to Jun 5
Start indoors: Mar 13 to Mar 27Transplant outside: May 15 to May 29
Start indoors: Mar 13 to Mar 27Transplant outside: Apr 17 to May 1Sow outdoors: Apr 10 to May 15Plant for fall: Aug 7 to Sep 4
Start indoors: Mar 13 to Mar 27Transplant outside: Apr 10 to Apr 24Sow outdoors: Apr 10 to Apr 24Plant for fall: Jul 24 to Aug 14
Start indoors: Mar 13 to Mar 27Transplant outside: Apr 24 to May 8Plant for fall: Jun 26 to Jul 17
Start indoors: Mar 13 to Mar 27Transplant outside: Apr 17 to May 1Plant for fall: Jun 26 to Jul 17
Start indoors: Mar 13 to Mar 27Transplant outside: Apr 24 to May 8Plant for fall: Jun 26 to Jul 17
Start indoors: Mar 27 to Apr 10Transplant outside: May 29 to Jun 12Sow outdoors: May 29 to Jun 12
Start indoors: Mar 27 to Apr 10Transplant outside: May 15 to May 29
Sow outdoors: Mar 27 to Apr 17Plant for fall: Jul 10 to Jul 31
Sow outdoors: Mar 27 to Apr 17Plant for fall: Aug 7 to Aug 28
Sow outdoors: Apr 3 to May 15Plant for fall: Aug 21 to Sep 11
Start indoors: Apr 10 to Apr 17Transplant outside: May 22 to May 29Sow outdoors: May 15 to May 29Plant for fall: Jul 17 to Jul 31
Start indoors: Apr 10 to Apr 17Sow outdoors: May 15 to May 29Plant for fall: Jul 24 to Aug 7
Start indoors: Apr 10 to Apr 17Sow outdoors: May 15 to May 29
Start indoors: Apr 10 to Apr 17Transplant outside: May 22 to Jun 5
Sow outdoors: Apr 17 to May 15Plant for fall: Jul 10 to Jul 24
Sow outdoors: Apr 17 to May 15Plant for fall: Jul 24 to Aug 7
Sow outdoors: Apr 17 to May 8
Sow outdoors: Apr 24 to May 22Plant for fall: Jul 24 to Aug 7
Sow outdoors: Apr 24 to May 15Plant for fall: Aug 7 to Aug 28
Sow outdoors: May 15 to Jun 5Plant for fall: Jul 17 to Jul 31
Sow outdoors: May 15 to May 29
Transplant outside: May 22 to Jun 12
Plant for fall: Sep 18 to Oct 23
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Smithfield, UT
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Feb 13 – Feb 27 | Apr 10 – Apr 24 | — | — |
| Peppers | Feb 27 – Mar 13 | May 22 – Jun 5 | — | — |
| Eggplant | Feb 27 – Mar 13 | May 22 – Jun 5 | — | — |
| Tomatoes | Mar 13 – Mar 27 | May 15 – May 29 | — | — |
| Lettuce | Mar 13 – Mar 27 | Apr 17 – May 1 | Apr 10 – May 15 | Aug 7 – Sep 4 |
| Kale | Mar 13 – Mar 27 | Apr 10 – Apr 24 | Apr 10 – Apr 24 | Jul 24 – Aug 14 |
| Broccoli | Mar 13 – Mar 27 | Apr 24 – May 8 | — | Jun 26 – Jul 17 |
| Cabbage | Mar 13 – Mar 27 | Apr 17 – May 1 | — | Jun 26 – Jul 17 |
| Cauliflower | Mar 13 – Mar 27 | Apr 24 – May 8 | — | Jun 26 – Jul 17 |
| Okra | Mar 27 – Apr 10 | May 29 – Jun 12 | May 29 – Jun 12 | — |
| Basil | Mar 27 – Apr 10 | May 15 – May 29 | — | — |
| Peas | — | — | Mar 27 – Apr 17 | Jul 10 – Jul 31 |
| Spinach | — | — | Mar 27 – Apr 17 | Aug 7 – Aug 28 |
| Radishes | — | — | Apr 3 – May 15 | Aug 21 – Sep 11 |
| Cucumbers | Apr 10 – Apr 17 | May 22 – May 29 | May 15 – May 29 | Jul 17 – Jul 31 |
| Zucchini & Summer Squash | Apr 10 – Apr 17 | — | May 15 – May 29 | Jul 24 – Aug 7 |
| Winter Squash & Pumpkins | Apr 10 – Apr 17 | — | May 15 – May 29 | — |
| Melons & Watermelon | Apr 10 – Apr 17 | May 22 – Jun 5 | — | — |
| Carrots | — | — | Apr 17 – May 15 | Jul 10 – Jul 24 |
| Beets | — | — | Apr 17 – May 15 | Jul 24 – Aug 7 |
| Potatoes | — | — | Apr 17 – May 8 | — |
| Swiss Chard | — | — | Apr 24 – May 22 | Jul 24 – Aug 7 |
| Cilantro | — | — | Apr 24 – May 15 | Aug 7 – Aug 28 |
| Green Beans | — | — | May 15 – Jun 5 | Jul 17 – Jul 31 |
| Sweet Corn | — | — | May 15 – May 29 | — |
| Sweet Potatoes | — | May 22 – Jun 12 | — | — |
| Garlic | — | — | — | Sep 18 – Oct 23 |
Dates come from the median frost dates and common extension-service timing. Adjust for your soil temperature, microclimate and the varieties you grow.
About these dates
Based on 1991–2020 NOAA climate normals for the Logan Cache Ap, UT weather station, 6 km away (elevation 4,455 ft (1,358 m)).
Frost dates near Smithfield
- Hyde Park May 8 · Oct 2
- Trenton May 17 · Sep 18
- Richmond May 11 · Oct 5
- Newton May 3 · Oct 12
- Cache Junction May 3 · Oct 12
- Logan May 8 · Oct 2
- Lewiston May 17 · Sep 18
- Cornish May 17 · Sep 18
- Providence Apr 30 · Oct 16
- Mendon May 12 · Sep 28
Frequently asked questions
When is the last frost in Smithfield, UT?
The median last spring frost in Smithfield, UT is May 8. There is still about a 10% chance of frost after May 29, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Smithfield, UT?
The median first fall frost is October 2, with about a 10% chance of frost before September 19.
How long is the growing season in Smithfield, UT?
About 147 days between the median last spring frost and first fall frost.
What planting zone is Smithfield, UT?
Smithfield, UT is in USDA hardiness zone 6a.