USDA Hardiness Zone 6a
Frost Dates for 84317 — Huntsville, Utah
NOAA 1991–2020 normals from Huntsville Monastery, UT (5,140 ft), 3 miles south.
Updated
In Huntsville, the last spring frost (32°F) is around June 4 in half of years and has passed by June 22 in nine years out of ten. The first fall frost comes around September 16, as early as September 1 one year in ten, leaving a typical freeze-free season of 102 days (NOAA, Huntsville Monastery, UT).
- Last spring frost
- June 4
- First fall frost
- September 16
- Growing season
- 102 days
- Hardiness zone
- 6a
50% probability
50% probability
freeze-free, 50%
-10 to -5°F (-23.3 to -20.6°C) coldest night
- First snow
- November 11
- Last snow
- April 14
- Winters with snow
- 94%
- Snow per year
- 82.4"
median, 1991–2020
median, 1991–2020
17 of 18 observed
NOAA normal
Frost risk by date in Huntsville
Half of springs at Huntsville Monastery, UT see their last 32°F night by June 4; only one in ten is past it by May 15, and one in ten still has one after June 22. Planting tender crops after June 11 leaves a 30% risk of a frost on them, after June 16 20%, and after June 22 10%. The 18 days between the even-odds date and the one-in-ten date is narrower than at 47% of the 66 Utah stations behind this site's ZIP pages.
In fall the first 32°F night comes by September 16 in half of years, as early as September 1 one year in ten, and holds off past October 1 one year in ten. A hard freeze of 28°F follows 12 days later, around September 28; in spring the one-in-ten date for 28°F is June 7, 15 days before the 32°F one. The freeze-free season lasts 102 days in a typical year, shorter than at 89% of the 66 Utah stations; it reaches 124 days one year in ten and falls short of 78 one year in ten. On average 204 nights a year drop to 32°F or below. Severe cold of 16°F or below comes every winter, usually between November 3 and March 23.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | too rare for a date | ||||||||
| 32°F | May 15 | May 22 | May 27 | Jun 1 | Jun 4 | Jun 8 | Jun 11 | Jun 16 | Jun 22 |
| 28°F | Apr 28 | May 2 | May 5 | May 9 | May 13 | May 18 | May 26 | Jun 1 | Jun 7 |
| 24°F | Apr 9 | Apr 15 | Apr 19 | Apr 22 | Apr 26 | Apr 29 | May 3 | May 7 | May 16 |
| 20°F | Mar 21 | Mar 27 | Mar 31 | Apr 3 | Apr 7 | Apr 10 | Apr 14 | Apr 20 | Apr 26 |
| 16°F | Mar 5 | Mar 11 | Mar 15 | Mar 19 | Mar 23 | Mar 28 | Mar 31 | Apr 3 | Apr 8 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | too rare for a date | ||||||||
| 32°F | Sep 1 | Sep 6 | Sep 10 | Sep 13 | Sep 16 | Sep 19 | Sep 22 | Sep 26 | Oct 1 |
| 28°F | Sep 12 | Sep 18 | Sep 21 | Sep 25 | Sep 28 | Oct 1 | Oct 3 | Oct 7 | Oct 12 |
| 24°F | Sep 23 | Sep 29 | Oct 3 | Oct 6 | Oct 10 | Oct 14 | Oct 18 | Oct 21 | Oct 25 |
| 20°F | Oct 5 | Oct 14 | Oct 18 | Oct 21 | Oct 24 | Oct 27 | Oct 30 | Nov 2 | Nov 8 |
| 16°F | Oct 19 | Oct 25 | Oct 29 | Nov 1 | Nov 3 | Nov 6 | Nov 10 | Nov 15 | Nov 21 |
Freeze probabilities 1991–2020 at Huntsville Monastery, 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 84317 →Compare Huntsville with another place →
Weather by month in Huntsville
July is the warmest month at Huntsville Monastery, UT, averaging 90°F by day and 49°F at night; January is the coldest at 34°F and 11°F. A freezing night is all but certain in every month from October to May (a 90% chance or more). From July to August the chance of a 32°F night stays under 10% each month. In spring, June still brings one in 59% of years.
Warmth for growing adds up to 2,082 growing degree days a year (base 50°F), fewer than at 79% of the 66 Utah stations. 28% of them (573) have built up by the end of June, and July adds the most, 604. Precipitation totals 21.1 inches a year, most in January (2.8") and least in July (0.7"); May to September bring 29% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 34 | 11 | 2.8 | 100% | 31 | 0 |
| Feb | 41 | 15 | 2.2 | 100% | 27 | 0 |
| Mar | 51 | 24 | 2.0 | 100% | 28 | 2 |
| Apr | 60 | 31 | 1.9 | 100% | 20 | 33 |
| May | 71 | 37 | 2.1 | 99% | 10 | 168 |
| Jun | 82 | 43 | 1.3 | 59% | 2 | 370 |
| Jul | 90 | 49 | 0.7 | 2% | <1 | 604 |
| Aug | 89 | 47 | 0.8 | 8% | <1 | 564 |
| Sep | 79 | 39 | 1.3 | 87% | 7 | 288 |
| Oct | 64 | 30 | 1.8 | 100% | 21 | 51 |
| Nov | 48 | 22 | 1.8 | 100% | 27 | 2 |
| Dec | 35 | 13 | 2.4 | 100% | 30 | 0 |
Monthly normals 1991–2020 at Huntsville Monastery, UT (5,140 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, Eden-Liberty, UT, 8 miles northwest of Huntsville, has a last frost 10 days earlier (May 25), a first frost 10 days later (September 26), a season 21 days longer.
When it snows in Huntsville, Utah
The first measurable snow (0.1 inch or more) in Huntsville usually arrives around November 11, and the last of the season around April 14. Those are the middle dates across the winters of 1991–2020 at Huntsville Monastery, UT, 3.4 miles away: half of years saw snow earlier, half later. Snow fell in 94% of those winters. The last 32°F night of spring typically comes 51 days after the last snow.
Planting calendar for 84317
| When | What to do |
|---|---|
| March 26 – April 9 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| April 9 – April 23 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| May 7 – May 21 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| June 4 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by June 24 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by September 2 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| September 16 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 84317 is 3 miles from Huntsville Monastery, UT, which stands at 5,140 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 84317 in zone 6a, the band where the coldest night of the year averaged -10 to -5°F (-23.3 to -20.6°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.