Salt Lake City, UT Frost Dates: Last Spring and First Fall Frost

In a typical year the final freeze of spring reaches Salt Lake City around March 31, and the first freeze of autumn returns around November 8. NOAA's normals call the frost-free stretch between them 224 days long.

Put April 19 and October 23 on the calendar as well. A spring freeze after the first of them, or a fall freeze before the second, happens in only one year out of ten, so those dates cover nine years in ten. The 100 cities covered here have a median season of 229 days, and Salt Lake City is close to it.

Behind every date on this page is one weather station, Salt Lake Triad Center (NOAA USC00427606), 1.9 miles east of Salt Lake City's internal point in the Census Bureau's files and about 4,300 feet up.

Last spring frost in Salt Lake City

Frost is still possible on March 7 in nine springs out of ten and on March 31 in five; only one spring in ten sees a freeze as late as April 19.

There are 43 days between the early and late dates, a broader band than most cities on these pages show. In Salt Lake City the typical date is a weaker promise than it looks.

When is the first frost in Salt Lake City?

A first freeze on or before October 23 happens one fall in ten. By November 8 half of years have had one, and by November 25 nine years in ten have.

Fall dates in Salt Lake City spread over 33 days, about the same as the middle of the 100 cities on these pages.

How long is the frost-free season in Salt Lake City?

The season is about as long as the middle of these pages. A typical year gives 224 days, but nine years in ten still give at least 195 days; 29 days separate the two, a larger swing than most cities here show, so a crop that needs the full typical season is a gamble in Salt Lake City.

The season lengths come from NOAA's simulated years, not from subtracting one typical date from the other, so the two will not match to the day. Every winter in the record reached freezing at Salt Lake Triad Center, so the dates above describe a real yearly event, not a rare one.

Hard freeze dates for Salt Lake City

A wide gap separates 32°F from 28°F here: the typical hard freeze arrives 10 days after the first frost in fall (November 18) and leaves 23 days before the last in spring (March 8). Frost-tolerant crops get a long extension at both ends. At the edges, a 28°F night on or after April 2 happens one spring in ten and one by November 1 one fall in ten; the nine-in-ten dates are February 17 and December 6.

Using Salt Lake City's frost dates in the garden

University of New Hampshire Extension sorts vegetables by how they cope with cold. Cool-season crops go out before the last frost: counting from March 31, cabbage transplants go in on March 3 and lettuce from March 3 to March 10. Tender crops wait until it has passed, with peppers going out on April 14 and beans sown on or after March 31. Peas have no frost-based date in the University of New Hampshire Extension sheet: they go in as soon as the soil thaws.

The late date comes 19 days after the typical one; choose it for plants you cannot cover.

Salt Lake City's first frost leaves room for only 32 of the 34 fall crops, counting back NC State Extension's days to harvest and University of Georgia Extension's harvest allowance of 18 days; for the other 2 the last planting day falls before July. The slowest crop that still fits is lima/pole beans, which needs 113 days before the early first frost and so must be in by July 2.

Worked example: fall broccoli in Salt Lake City

Take fall broccoli in Salt Lake City. NC State Extension lists up to 80 days from transplant to harvest, and University of Georgia Extension adds a harvest allowance of 18 days, so the plants need 98 days before the first frost. Counting back from the typical first frost, November 8, the last planting day is August 2. Counting back from the early date, October 23, it is July 17.

16 days separate the two last days, enough that in Salt Lake City the earlier one is worth following.

In spring the same family goes in earlier: counting from March 31, University of New Hampshire Extension puts cabbage transplants out on March 3, weeks ahead of the last frost.

About the Salt Lake Triad Center station

The station is 1.9 miles east of the Census Bureau's internal point for Salt Lake City, close enough that its record is the natural reference for the city.

At about 4,300 feet, it ranks above 94 and below 5 of the 100 stations used for these pages. In NOAA's file the record is marked R, meaning representative.

No elevation is available for Salt Lake City in the Census data we saved, so the station's height may or may not match your garden's. Compare nearby stations in the frost dates tool if it does not, and err toward the colder dates.

Salt Lake City compared with nearby cities

No other city in this set lies within 150 miles of Salt Lake City; the nearest is Boise, ID, 294 miles away, so the comparison below crosses real climate differences, not a county line. Elevation differs: the station for Boise is 1,500 feet below the one for Salt Lake City, which is worth remembering when you compare them.

• Boise, ID (294 miles, north-west): its last frost comes 24 days after Salt Lake City's, and it has 45 days less without frost. Its typical dates are April 24 and October 21, with 179 days frost-free.
• North Las Vegas, NV lies 354 miles south-west of Salt Lake City. Typical last frost February 1, first frost December 8, 311 days between; its last frost comes 58 days before Salt Lake City's, and the frost-free season is 87 days longer than Salt Lake City's.
• Las Vegas, NV (362 miles, south-west): its last frost comes 66 days before Salt Lake City's, and it has 99 days more without frost. Its typical dates are January 24 and December 10, with 323 days frost-free.

Next steps for Salt Lake City gardeners

Open the frost dates tool with this station already chosen to see the whole ladder of probability dates, or try the nearby stations in the same list. The spring planting planner and the fall planting planner turn the same dates into a full crop list, and the hardiness zone lookup tells you which perennials will survive the winter.

Every city covered is on the city frost dates index, sorted by state.

Where these numbers come from

The frost and freeze dates are NOAA's U.S. Climate Normals for 1991–2020 (doi:10.25921/4ek7-fk11), copied from the station's own record without adjustment; NOAA's documentation defines each probability. Salt Lake City and its internal point are listed in the Census Bureau's 2024 Gazetteer of places; its place in the ranking comes from the Vintage 2024 population estimates, which count 217,783 residents.

The planting dates apply the count rules in University of New Hampshire Extension, NC State Extension and University of Georgia Extension to this station's dates, with nothing added. The methodology page explains how each figure is checked.

Frost dates are long-term odds, not a forecast. Before you plant, check the local forecast for the coming week, and keep row cover or old sheets handy for the nights the odds get wrong.