Frost dates for Salt Lake City, Utah
In Salt Lake City, half of springs have had their last frost by April 8 (and 1 spring in 10 still has one after April 30), and half of falls have had their first frost by October 31, leaving about 204 frost-free days in a typical year. Here is how sure those dates are, what they mean for planting, and where they come from.
Frost dates for
Salt Lake City, Utah
Last spring frost
April 8
Half of springs have their last frost by this date. For a safer bet, wait until April 30: only 1 spring in 10 has a frost after that.
First fall frost
October 31
Half of falls have their first frost by this date. In 1 fall in 10 it comes by October 17.
Growing season
204 days
Frost-free days in a typical year. 9 years in 10 get at least 177.
Hardiness zone
6b
2023 USDA map: the coldest night of winter averages −5°F to 0°F. On the 2012 map it was 7a, half a zone warmer. ZIP codes within about 6 miles of the city's center: 2 in 6b, 2 in 7a and 11 in 7b.
Stations near you disagree. NOAA's Salt Lake City International Airport (2 miles away, at 4,230 feet above sea level), the one we used, gives a typical last frost of April 8 and a typical first frost of October 31. NOAA's City Creek WTP (6 miles away, at 5,340 feet above sea level) gives a typical last frost of May 13 and a typical first frost of October 7. So the typical last frost could fall anywhere from April 8 to May 13 and the typical first frost from October 7 to 31, depending on whether your garden is more like one or the other. Local terrain matters: hillsides, valley floors, water and city heat can change frost dates a lot over a few miles. Treat the dates here as a starting point, and compare with a nearby gardener or your county extension office.
Print a year planner for Salt Lake City
Frost risk through the year
How sure are these dates?
A frost date is a probability, not a promise. NOAA worked out, from 30 years of nightly lows, how often the last spring frost and the first fall frost fall on each date. The middle column is the typical year. The outer columns are the early and late years that come about once a decade.
| Early year 1 in 10 | Typical year 1 in 2 | Late year 1 in 10 | |
|---|---|---|---|
| Last frost in spring | March 17 | April 8 | April 30 |
| First frost in fall | October 17 | October 31 | November 13 |
The frost-free season between them runs 204 days in a typical year. In 1 year in 10 it is 229 days or longer, and in 1 year in 10 it is 177 days or shorter.
- Hard freeze (28°F): typically last on March 15 and first on November 10. It is a harder freeze than the 32°F frost line, cold enough to damage many garden plants; how hardy a crop is decides whether it comes through. (The National Weather Service's own hard-freeze threshold varies from office to office.)
- Frost possible (36°F at the station): typically last on April 27 and first on October 19. On clear, still nights the ground can be several degrees colder than the thermometer, so frost can form on plants when the official reading is in the mid-30s.
In 8 springs out of 10, the last frost in Salt Lake City comes between March 17 and April 30, a window of 44 days. That is wider than at most NOAA stations (the typical window is 31 days), so spring here is less predictable than average: lean toward the later date.
Among Utah's 169 NOAA stations with a frost every year, 93 percent have their typical last frost later than Salt Lake City does.
Planting calendar for Salt Lake City
These dates count from the typical last and first frosts, using the planting rules published by Colorado State University Extension (spring), Virginia Cooperative Extension (fall crops) and University of Minnesota Extension (garlic, where winters are hard). Weather in any one year can run early or late, so check the forecast before you plant tender crops.
| When | What to do | Why then |
|---|---|---|
| January | ||
| January 21 to February 18 | Broccoli and cabbage Start seeds indoors | 5 to 7 weeks before planting them out |
| February | ||
| February 4 to March 4 | Cauliflower Start seeds indoors | 5 to 7 weeks before planting out |
| February 18 to March 11 | Eggplant Start seeds indoors | 6 to 9 weeks before planting out |
| February 25 to March 11 | Peppers Start seeds indoors | 6 to 8 weeks before planting out |
| March | ||
| March 4 to 18 | Tomatoes Start seeds indoors | 5 to 7 weeks before planting out |
| March 11 to 25 | Peas, spinach, lettuce, radishes, onion sets, turnips Sow outdoors, as early as | hardy crops: 2 to 4 weeks before the typical last frost |
| March 11 to 25 | Broccoli and cabbage Plant out, as early as | hardy crops: 2 to 4 weeks before the typical last frost |
| March 25 to April 8 | Beets, carrots, potatoes, Swiss chard Plant outdoors, as early as | semi-hardy crops: up to 2 weeks before the typical last frost |
| March 25 to April 8 | Cauliflower Plant out, as early as | semi-hardy: up to 2 weeks before the typical last frost |
| April | ||
| April 8 | Snap beans, sweet corn, cucumbers, summer squash Sow outdoors around | tender crops: around the typical last frost date |
| April 22 | Tomatoes, peppers, eggplant Plant out from | very tender: 2 weeks or more after the typical last frost |
| April 22 | Melons, winter squash, pumpkins, lima beans Sow outdoors from | very tender: 2 weeks or more after the typical last frost |
| June | ||
| June 5 to 19 | Cabbage for fall Start seeds | set the plants out by July 24 |
| June 25 to July 9 | Broccoli for fall Start seeds | set the plants out by August 13 |
| August | ||
| August 4 | Snap beans for fall Last date to sow | 60 days to harvest, plus 2 weeks for slower fall growth, plus 2 weeks because frost kills it |
| August 8 | Carrots for fall Last date to sow | 70 days to harvest, plus 2 weeks for slower fall growth |
| August 9 | Cucumbers for fall Last date to sow | 55 days to harvest, plus 2 weeks for slower fall growth, plus 2 weeks because frost kills it |
| August 13 | Peas for fall Last date to sow | 65 days to harvest, plus 2 weeks for slower fall growth |
| August 14 | Summer squash for fall Last date to sow | 50 days to harvest, plus 2 weeks for slower fall growth, plus 2 weeks because frost kills it |
| August 18 | Leaf lettuce and beets for fall Last date to sow | 60 days to harvest, plus 2 weeks for slower fall growth |
| August 28 | Turnips and kohlrabi for fall Last date to sow | 50 days to harvest, plus 2 weeks for slower fall growth |
| September | ||
| September 7 | Spinach for fall Last date to sow | 40 days to harvest, plus 2 weeks for slower fall growth |
| September 17 | Radishes for fall Last date to sow | 30 days to harvest, plus 2 weeks for slower fall growth |
| October | ||
| October 17 | Tomatoes, peppers, squash, melons, cucumbers Watch the forecast from | in 1 fall in 10 the first frost comes by this date; pick tender crops before a frost |
| November | ||
| November 17 to 24 | Garlic Plant cloves | one or two weeks after the typical first hard freeze (28°F), our reading of the first killing frost |
Want more insurance? Shift every spring date 22 days later. That plans around April 30, the date after which only 1 spring in 10 has a frost.
For spring bulbs such as tulips and daffodils, plant once the soil has cooled to about 50 to 55°F and keep going until a couple of weeks before the ground freezes. Our guide to fall planting explains how to tell.
Where these numbers come from
These dates come from NOAA's weather station Salt Lake City International Airport (station USW00024127), 2 miles from the center of Salt Lake City. It sits at about the same elevation, 4,230 feet above sea level. NOAA rates this station's record as standard: at least 24 of the 30 years, with gaps filled from nearby stations.
The same station also gives the frost dates for West Valley City, Taylorsville, Murray, Midvale, Magna, Holladay, South Salt Lake and North Salt Lake.
Our ZIP code lookup matches these 7 ZIP codes to the same station, so they get the same dates: 84087, 84103, 84104, 84108, 84116, 84120, 84128. Hardiness zones are worked out separately for each ZIP code.
Nearby places
- West Jordan, Utah: last frost around April 18, first frost around October 22 (15 miles away)
- Provo, Utah: last frost around April 18, first frost around October 21 (40 miles away)
See frost dates across Utah, or look up your own ZIP code for the station nearest you. Want the background? Read what a last frost date really means.