First & Last Frost Dates in Utah (2026)
Typical first freeze October 8 · last spring frost May 2 · about 160 growing days between them.
First frost approaching — typically 10 days outWhere Utah sits on the frost line
NOAA 1991 to 2020 normalsSt. George's Mojave corner gardens like Las Vegas while Cache Valley frosts like Montana — Utah spans four zones in 300 miles.
Frost dates for your exact ZIP
The dates above are the state median. Enter a ZIP code to snap to the nearest of 150 NOAA reference stations and read that station’s own first and last freeze instead:
Frost dates across Utah
State averages hide huge local spread — elevation, cold-air drainage, urban heat, and nearby water routinely move frost dates by two to four weeks within the same state. Median dates for representative Utah stations:
| City | Typical first frost | Typical last frost |
|---|---|---|
| Salt Lake City | October 16 | April 22 |
| St. George | November 8 | March 20 |
| Logan | September 28 | May 12 |
Not near these cities? The ZIP lookup above snaps any US address to its nearest reference station. It is the same tool as the site’s national frost date lookup.
Your Utah first-frost playbook
The Utah planting calendar
Every date below is computed from Utah’s own frost anchors — last frost ~May 2, first frost ~October 8 — using the standard week-count rules seed packets assume. Shift everything a few days for your microclimate (see the city table above).
| Garden task | Typical Utah date | The rule it comes from |
|---|---|---|
| Start onions & leeks indoors | February 21 | ~10 weeks before last frost |
| Start peppers & tomatoes indoors | March 7 | ~8 weeks before last frost |
| Direct-sow peas & spinach | March 28 | ~5 weeks before last frost |
| Plant potatoes | April 18 | ~2 weeks before last frost |
| Transplant tomatoes & peppers out | May 27 | ~1 week after the late frost date |
| Sow fall carrots (70-day) | July 15 | ~12 weeks before first frost |
| Sow fall spinach & lettuce | August 19 | ~7 weeks before first frost |
| Plant garlic | October 22 | ~2 weeks after first frost |
Two rules do most of the work: count backward from first frost for fall crops (a 70-day carrot needs sowing ~12 weeks out, because fall growth slows as days shorten), and count forward from the late last-frost date — not the median — for anything frost-tender going outside.
What dies at what temperature
“Frost” isn’t one event. Surfaces can frost with air temps as high as 36–37°F on calm clear nights; a freeze is 32°F; a hard freeze is 28°F and ends the season for anything unprotected. Crops check out at very different points along the way:
| Crops | Damage point | What it means |
|---|---|---|
| Basil, impatiens, coleus, sweet potato vine | 38–40°F | Damaged before an official frost even hits |
| Tomatoes, peppers, cucumbers, squash, beans | 32°F | Killed by the first light freeze |
| Lettuce, chard, cilantro, peas | 28°F | Shrug off light frost; done at a hard freeze |
| Broccoli, cabbage, carrots, beets | 25°F | Keep producing weeks past first frost |
| Kale, spinach, Brussels sprouts, parsnips | 15–20°F | Frost makes them sweeter — harvest all late fall |
The practical read for Utah: once you’re inside the September 20–October 24 window, the top two rows are living on borrowed time — while the bottom two rows are just getting started. Frost converts starches to sugars in kale, carrots, and parsnips; the sweetest harvests of the year come after first frost.
Utah frost date FAQ
Plan the rest of the season
More Rockies frost dates
Dates are median first/last 32°F freeze approximations from NOAA 1991–2020 climate normals for representative stations, bracketed by roughly the 10%/90% range. Any single year varies; microclimates vary more. National picture: first frost dates for every state