USDA Hardiness Zone 6b
Frost Dates for 84103 — Salt Lake City, Utah
NOAA 1991–2020 normals from Salt Lake Triad Ctr, UT (4,280 ft), 1 miles southwest.
Updated
In Salt Lake City, the last spring frost (32°F) is around March 31 in half of years and has passed by April 19 in nine years out of ten. The first fall frost comes around November 8, as early as October 23 one year in ten, leaving a typical freeze-free season of 224 days (NOAA, Salt Lake Triad Ctr, UT).
- Last spring frost
- March 31
- First fall frost
- November 8
- Growing season
- 224 days
- Hardiness zone
- 6b
50% probability
50% probability
freeze-free, 50%
-5 to 0°F (-20.6 to -17.8°C) coldest night
- First snow
- November 4
- Last snow
- April 16
- Winters with snow
- 100%
- Snow per year
- 49"
median, 1991–2020
median, 1991–2020
22 of 22 observed
NOAA normal
Frost risk by date in Salt Lake City
Half of springs at Salt Lake Triad Ctr, UT see their last 32°F night by March 31; only one in ten is past it by March 7, and one in ten still has one after April 19. Planting tender crops after April 7 leaves a 30% risk of a frost on them, after April 12 20%, and after April 19 10%. The 19 days between the even-odds date and the one-in-ten date is wider than at 55% of the 66 Utah stations behind this site's ZIP pages.
In fall the first 32°F night comes by November 8 in half of years, as early as October 23 one year in ten, and holds off past November 25 one year in ten. A hard freeze of 28°F follows 10 days later, around November 18; in spring the one-in-ten date for 28°F is April 2, 17 days before the 32°F one. The freeze-free season lasts 224 days in a typical year, longer than at 98% of the 66 Utah stations; it reaches 254 days one year in ten and falls short of 195 one year in ten. On average 81 nights a year drop to 32°F or below. Nights of 36°F, when frost can still settle on leaves in low, open spots, continue 18 days longer, to about April 18, and return around October 28. Nights of 24°F, cold enough to damage hardier plants, come in 100% of winters and 16°F in 85%.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Mar 28 | Apr 3 | Apr 8 | Apr 13 | Apr 18 | Apr 21 | Apr 26 | May 1 | May 9 |
| 32°F | Mar 7 | Mar 13 | Mar 19 | Mar 26 | Mar 31 | Apr 3 | Apr 7 | Apr 12 | Apr 19 |
| 28°F | Feb 17 | Feb 24 | Feb 28 | Mar 3 | Mar 8 | Mar 11 | Mar 15 | Mar 27 | Apr 2 |
| 24°F | Jan 31 | Feb 6 | Feb 11 | Feb 15 | Feb 19 | Feb 24 | Feb 28 | Mar 4 | Mar 10 |
| 20°F98% of yrs | Jan 3 | Jan 17 | Jan 26 | Jan 31 | Feb 3 | Feb 7 | Feb 13 | Feb 19 | Feb 27 |
| 16°F85% of yrs | Dec 20 | Dec 31 | Jan 7 | Jan 14 | Jan 22 | Jan 28 | Feb 1 | Feb 6 | Feb 13 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Oct 12 | Oct 17 | Oct 22 | Oct 25 | Oct 28 | Oct 31 | Nov 3 | Nov 7 | Nov 13 |
| 32°F | Oct 23 | Oct 28 | Nov 1 | Nov 5 | Nov 8 | Nov 11 | Nov 15 | Nov 20 | Nov 25 |
| 28°F | Nov 1 | Nov 7 | Nov 11 | Nov 15 | Nov 18 | Nov 23 | Nov 26 | Dec 1 | Dec 6 |
| 24°F | Nov 11 | Nov 17 | Nov 21 | Nov 25 | Nov 29 | Dec 3 | Dec 7 | Dec 11 | Dec 17 |
| 20°F98% of yrs | Nov 19 | Nov 26 | Nov 30 | Dec 6 | Dec 11 | Dec 15 | Dec 20 | Dec 25 | Jan 3 |
| 16°F85% of yrs | Nov 28 | Dec 6 | Dec 14 | Dec 19 | Dec 25 | Dec 28 | Jan 2 | Jan 10 | Jan 24 |
Freeze probabilities 1991–2020 at Salt Lake Triad Ctr, UT, from NOAA NCEI U.S. Climate Normals. Where a temperature is reached in fewer than 99.5% of years, the dates describe only the years that reach it. Not a forecast.
Frost risk on any date in 84103 →Compare Salt Lake City with another place →
Weather by month in Salt Lake City
July is the warmest month at Salt Lake Triad Ctr, UT, averaging 91°F by day and 70°F at night; January is the coldest at 40°F and 28°F. A freezing night is all but certain in every month from November to March (a 90% chance or more). From May to September the chance of a 32°F night stays under 10% each month. In spring, April still brings one in 45% of years.
Warmth for growing adds up to 3,943 growing degree days a year (base 50°F), more than at 94% of the 66 Utah stations. 32% of them (1,253) have built up by the end of June, and July adds the most, 950. Precipitation totals 17.8 inches a year, most in April (2.5") and least in July (0.6"); May to September bring 32% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 40 | 28 | 1.5 | 100% | 22 | 1 |
| Feb | 46 | 31 | 1.5 | 100% | 16 | 5 |
| Mar | 56 | 39 | 2.0 | 92% | 6 | 57 |
| Apr | 62 | 44 | 2.5 | 45% | 2 | 153 |
| May | 72 | 52 | 2.1 | 2% | 0 | 388 |
| Jun | 83 | 61 | 1.1 | 0% | 0 | 649 |
| Jul | 91 | 70 | 0.6 | 0% | 0 | 950 |
| Aug | 90 | 68 | 0.6 | 0% | 0 | 893 |
| Sep | 80 | 58 | 1.3 | 0% | 0 | 571 |
| Oct | 66 | 47 | 1.4 | 28% | 2 | 234 |
| Nov | 52 | 37 | 1.6 | 93% | 10 | 40 |
| Dec | 41 | 28 | 1.6 | 100% | 23 | 3 |
Monthly normals 1991–2020 at Salt Lake Triad Ctr, UT (4,280 ft), NOAA NCEI. "32°F night": chance of at least one in the month. GDD: growing degree days, base 50°F.
Compared with the next station
The nearest other station, Salt Lake City E Bench, UT, 4 miles southeast of Salt Lake City and 570 feet higher, has a last frost 25 days later (April 25), a first frost 21 days earlier (October 18), a season 49 days shorter.
When it snows in Salt Lake City, Utah
The first measurable snow (0.1 inch or more) in Salt Lake City usually arrives around November 4, and the last of the season around April 16. Those are the middle dates across the winters of 1991–2020 at Salt Lake Triad Ctr, UT, 1.2 miles away: half of years saw snow earlier, half later. Every one of those winters saw snow. The last 32°F night of spring typically comes 16 days before the last snow.
Planting calendar for 84103
| When | What to do |
|---|---|
| January 20 – February 3 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| February 3 – February 17 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| March 3 – March 17 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| March 31 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by August 16 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by October 25 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| November 8 onward | Plant garlic, mulch beds, lift tender bulbsGarlic wants a cold spell; bare soil loses structure over winter. |
The weeks before and after the 50% dates are general rules of thumb, not NOAA figures; a seed packet gives the timing for each variety.
Where these figures come from
ZIP 84103 is 1 mile from Salt Lake Triad Ctr, UT, which stands at 4,280 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 5 other ZIP codes share the station; its figures are presented in full for 84129 (Taylorsville). The 2023 USDA Plant Hardiness Zone Map lists ZIP 84103 in zone 6b, the band where the coldest night of the year averaged -5 to 0°F (-20.6 to -17.8°C) over 1991–2020; a zone describes winter lows, not frost dates.
Hardiness zone and temperature range: USDA Plant Hardiness Zone Map 2023 (USDA-ARS, Oregon State University), ZIP-code listing, unchanged. °C converted from °F by this site.
Thirty-year averages, not a forecast: check the forecast before planting out. How stations are matched and which pages are offered to search engines: methodology.