Frost dates for St. George, Utah
In St. George, half of springs have had their last frost by March 14 (and 1 spring in 10 still has one after April 6), and half of falls have had their first frost by November 10, leaving about 239 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
St. George, Utah
Last spring frost
March 14
Half of springs have their last frost by this date. For a safer bet, wait until April 6: only 1 spring in 10 has a frost after that.
First fall frost
November 10
Half of falls have their first frost by this date. In 1 fall in 10 it comes by October 27.
Growing season
239 days
Frost-free days in a typical year. 9 years in 10 get at least 212.
Hardiness zone
8b
2023 USDA map: the coldest night of winter averages 15°F to 20°F. On the 2012 map it was 8a, half a zone colder. All 2 ZIP codes within about 6 miles of the city's center are in zone 8b.
Print a year planner for St. George
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 | February 27 | March 14 | April 6 |
| First frost in fall | October 27 | November 10 | November 22 |
The frost-free season between them runs 239 days in a typical year. In 1 year in 10 it is 260 days or longer, and in 1 year in 10 it is 212 days or shorter.
- Hard freeze (28°F): typically last on February 27 and first on November 20. 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 3 and first on November 1. 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 St. George comes between February 27 and April 6, a window of 38 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, 99 percent have their typical last frost later than St. George does.
Planting calendar for St. George
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 10 to February 7 | Cauliflower Start seeds indoors | 5 to 7 weeks before planting out |
| January 24 to February 14 | Eggplant Start seeds indoors | 6 to 9 weeks before planting out |
| January 31 to February 14 | Peppers Start seeds indoors | 6 to 8 weeks before planting out |
| February | ||
| February 7 to 21 | Tomatoes Start seeds indoors | 5 to 7 weeks before planting out |
| February 14 to 28 | Peas, spinach, lettuce, radishes, onion sets, turnips Sow outdoors, as early as | hardy crops: 2 to 4 weeks before the typical last frost |
| February 14 to 28 | Broccoli and cabbage Plant out, as early as | hardy crops: 2 to 4 weeks before the typical last frost |
| February 28 to March 14 | Beets, carrots, potatoes, Swiss chard Plant outdoors, as early as | semi-hardy crops: up to 2 weeks before the typical last frost |
| February 28 to March 14 | Cauliflower Plant out, as early as | semi-hardy: up to 2 weeks before the typical last frost |
| March | ||
| March 14 | Snap beans, sweet corn, cucumbers, summer squash Sow outdoors around | tender crops: around the typical last frost date |
| March 28 | Tomatoes, peppers, eggplant Plant out from | very tender: 2 weeks or more after the typical last frost |
| March 28 | Melons, winter squash, pumpkins, lima beans Sow outdoors from | very tender: 2 weeks or more after the typical last frost |
| June | ||
| June 15 to 29 | Cabbage for fall Start seeds | set the plants out by August 3 |
| July | ||
| July 5 to 19 | Broccoli for fall Start seeds | set the plants out by August 23 |
| August | ||
| August 14 | 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 18 | Carrots for fall Last date to sow | 70 days to harvest, plus 2 weeks for slower fall growth |
| August 19 | 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 23 | Peas for fall Last date to sow | 65 days to harvest, plus 2 weeks for slower fall growth |
| August 24 | 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 28 | Leaf lettuce and beets for fall Last date to sow | 60 days to harvest, plus 2 weeks for slower fall growth |
| September | ||
| September 7 | Turnips and kohlrabi for fall Last date to sow | 50 days to harvest, plus 2 weeks for slower fall growth |
| September 17 | Spinach for fall Last date to sow | 40 days to harvest, plus 2 weeks for slower fall growth |
| September 27 | Radishes for fall Last date to sow | 30 days to harvest, plus 2 weeks for slower fall growth |
| October | ||
| October 27 | 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 27 to December 4 | Garlic Plant cloves | one or two weeks after the typical first hard freeze (28°F), our reading of the first killing frost |
| December | ||
| December 27 to January 24 | Broccoli and cabbage Start seeds indoors | 5 to 7 weeks before planting them out |
Want more insurance? Shift every spring date 23 days later. That plans around April 6, 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 St George (station USC00427516), 3 miles from the center of St. George. It sits 240 feet higher, at 2,860 feet above sea level. NOAA rates this station's record as representative: at least 10 of the 30 years, with the gaps filled from nearby stations.
The same station also gives the frost dates for Washington and Ivins.
Our ZIP code lookup matches these 4 ZIP codes to the same station, so they get the same dates: 84738, 84770, 84780, 84790. Hardiness zones are worked out separately for each ZIP code.
The nearest other places with pages
- Henderson, Nevada: frost not every year (105 miles away)
- Las Vegas, Nevada: frost not every year (110 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.