USDA Hardiness Zone 6a
Frost Dates for 84761 — Parowan, Utah
NOAA 1991–2020 normals from Brian Head, UT (9,770 ft), 13 miles south.
Updated
In Parowan, the last spring frost (32°F) is around June 21 in half of years and has passed by July 6 in nine years out of ten. The first fall frost comes around September 12, as early as September 1 one year in ten, leaving a typical freeze-free season of 82 days (NOAA, Brian Head, UT).
- Last spring frost
- June 21
- First fall frost
- September 12
- Growing season
- 82 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
- October 4
- Last snow
- June 9
- Winters with snow
- 100%
- Snow per year
- —
median, 1991–2020
median, 1991–2020
16 of 16 observed
NOAA normal
Frost risk by date in Parowan
Half of springs at Brian Head, UT see their last 32°F night by June 21; only one in ten is past it by June 6, and one in ten still has one after July 6. Planting tender crops after June 27 leaves a 30% risk of a frost on them, after June 30 20%, and after July 6 10%. The 15 days between the even-odds date and the one-in-ten date is narrower than at 89% of the 66 Utah stations behind this site's ZIP pages.
In fall the first 32°F night comes by September 12 in half of years, as early as September 1 one year in ten, and holds off past September 23 one year in ten. A hard freeze of 28°F follows 10 days later, around September 22; in spring the one-in-ten date for 28°F is June 24, 12 days before the 32°F one. The freeze-free season lasts 82 days in a typical year, the shortest of the 66 Utah stations; it reaches 100 days one year in ten and falls short of 63 one year in ten. On average 255 nights a year drop to 32°F or below. Severe cold of 16°F or below comes every winter, usually between October 19 and May 2.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | too rare for a date | ||||||||
| 32°F | Jun 6 | Jun 11 | Jun 14 | Jun 18 | Jun 21 | Jun 24 | Jun 27 | Jun 30 | Jul 6 |
| 28°F | May 25 | May 31 | Jun 2 | Jun 5 | Jun 7 | Jun 11 | Jun 14 | Jun 19 | Jun 24 |
| 24°F | May 11 | May 16 | May 20 | May 23 | May 28 | May 31 | Jun 3 | Jun 6 | Jun 13 |
| 20°F | Apr 30 | May 3 | May 6 | May 9 | May 12 | May 15 | May 18 | May 22 | May 31 |
| 16°F | Apr 18 | Apr 24 | Apr 27 | Apr 30 | May 2 | May 4 | May 6 | May 10 | May 16 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | too rare for a date | ||||||||
| 32°F | Sep 1 | Sep 4 | Sep 8 | Sep 10 | Sep 12 | Sep 14 | Sep 17 | Sep 19 | Sep 23 |
| 28°F | Sep 10 | Sep 14 | Sep 17 | Sep 20 | Sep 22 | Sep 24 | Sep 26 | Sep 28 | Oct 1 |
| 24°F | Sep 18 | Sep 23 | Sep 26 | Sep 29 | Oct 1 | Oct 3 | Oct 5 | Oct 8 | Oct 12 |
| 20°F | Sep 27 | Oct 1 | Oct 3 | Oct 6 | Oct 8 | Oct 11 | Oct 14 | Oct 17 | Oct 22 |
| 16°F | Oct 4 | Oct 8 | Oct 13 | Oct 16 | Oct 19 | Oct 22 | Oct 25 | Oct 29 | Nov 4 |
Freeze probabilities 1991–2020 at Brian Head, 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 84761 →Compare Parowan with another place →
Weather by month in Parowan
July is the warmest month at Brian Head, UT, averaging 71°F by day and 42°F at night; December is the coldest at 28°F and 10°F. A freezing night is all but certain in every month from September to June (a 90% chance or more). August is the only month with under a 10% chance of a 32°F night. In spring, July still brings one in 20% of years.
Warmth for growing adds up to 549 growing degree days a year (base 50°F), the fewest of the 66 Utah stations. 21% of them (117) have built up by the end of June, and July adds the most, 210.
| Month | High °F | Low °F | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|
| Jan | 30 | 10 | 100% | 31 | 0 |
| Feb | 32 | 12 | 100% | 28 | 0 |
| Mar | 39 | 17 | 100% | 31 | 0 |
| Apr | 44 | 18 | 100% | 30 | 0 |
| May | 55 | 27 | 100% | 25 | 14 |
| Jun | 67 | 36 | 97% | 8 | 104 |
| Jul | 71 | 42 | 20% | 1 | 210 |
| Aug | 69 | 43 | 9% | 1 | 179 |
| Sep | 61 | 35 | 99% | 12 | 42 |
| Oct | 48 | 24 | 100% | 29 | 0 |
| Nov | 38 | 17 | 100% | 29 | 0 |
| Dec | 28 | 10 | 100% | 31 | 0 |
Monthly normals 1991–2020 at Brian Head, UT (9,770 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, Cedar City Municipal Airport, UT, 19 miles southwest of Parowan and 4,184 feet lower, has a last frost 31 days earlier (May 21), a first frost 17 days later (September 29), a season 48 days longer.
When it snows in Parowan, Utah
The first measurable snow (0.1 inch or more) in Parowan usually arrives around October 4, and the last of the season around June 9. Those are the middle dates across the winters of 1991–2020 at Brian Head, UT, 13.3 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 12 days after the last snow.
Planting calendar for 84761
| When | What to do |
|---|---|
| April 12 – April 26 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| April 26 – May 10 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| May 24 – June 7 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| June 21 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by June 20 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by August 29 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| September 12 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 84761 is 13 miles from Brian Head, UT, which stands at 9,770 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 84761 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.