USDA Hardiness Zone 7b
Frost Dates for 28790 — Zirconia, North Carolina
NOAA 1991–2020 normals from Hendersonville 1 NE, NC (2,160 ft), 9 miles north.
Updated
In Zirconia, the last spring frost (32°F) is around April 14 in half of years and has passed by May 1 in nine years out of ten. The first fall frost comes around October 25, as early as October 12 one year in ten, leaving a typical freeze-free season of 192 days (NOAA, Hendersonville 1 NE, NC).
- Last spring frost
- April 14
- First fall frost
- October 25
- Growing season
- 192 days
- Hardiness zone
- 7b
50% probability
50% probability
freeze-free, 50%
5 to 10°F (-15.0 to -12.2°C) coldest night
- First snow
- Rare
- Last snow
- Rare
- Winters with snow
- 29%
- Snow per year
- 1.4"
median, 1991–2020
median, 1991–2020
7 of 24 observed
NOAA normal
Frost risk by date in Zirconia
Half of springs at Hendersonville 1 NE, NC see their last 32°F night by April 14; only one in ten is past it by March 31, and one in ten still has one after May 1. Planting tender crops after April 20 leaves a 30% risk of a frost on them, after April 24 20%, and after May 1 10%. The 17 days between the even-odds date and the one-in-ten date is wider than at 65% of the 173 North Carolina stations behind this site's ZIP pages.
In fall the first 32°F night comes by October 25 in half of years, as early as October 12 one year in ten, and holds off past November 6 one year in ten. A hard freeze of 28°F follows 9 days later, around November 3; in spring the one-in-ten date for 28°F is April 16, 15 days before the 32°F one. The freeze-free season lasts 192 days in a typical year, shorter than at 80% of the 173 North Carolina stations; it reaches 213 days one year in ten and falls short of 171 one year in ten. On average 88 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 13 days longer, to about April 27, and return around October 15. Severe cold of 16°F or below comes in 99% of winters, usually between December 19 and February 14.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Apr 12 | Apr 17 | Apr 20 | Apr 24 | Apr 27 | Apr 30 | May 3 | May 7 | May 14 |
| 32°F | Mar 31 | Apr 4 | Apr 7 | Apr 10 | Apr 14 | Apr 16 | Apr 20 | Apr 24 | May 1 |
| 28°F | Mar 15 | Mar 21 | Mar 26 | Mar 30 | Apr 2 | Apr 4 | Apr 6 | Apr 10 | Apr 16 |
| 24°F | Feb 27 | Mar 6 | Mar 11 | Mar 15 | Mar 19 | Mar 23 | Mar 27 | Mar 31 | Apr 4 |
| 20°F | Feb 6 | Feb 15 | Feb 22 | Feb 27 | Mar 3 | Mar 9 | Mar 14 | Mar 18 | Mar 25 |
| 16°F99% of yrs | Jan 15 | Jan 26 | Feb 1 | Feb 7 | Feb 14 | Feb 22 | Feb 28 | Mar 6 | Mar 14 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Oct 3 | Oct 8 | Oct 11 | Oct 13 | Oct 15 | Oct 19 | Oct 22 | Oct 25 | Oct 29 |
| 32°F | Oct 12 | Oct 16 | Oct 19 | Oct 22 | Oct 25 | Oct 28 | Oct 31 | Nov 2 | Nov 6 |
| 28°F | Oct 21 | Oct 26 | Oct 29 | Nov 1 | Nov 3 | Nov 5 | Nov 8 | Nov 12 | Nov 18 |
| 24°F | Nov 1 | Nov 4 | Nov 8 | Nov 11 | Nov 14 | Nov 18 | Nov 22 | Nov 28 | Dec 4 |
| 20°F | Nov 12 | Nov 16 | Nov 21 | Nov 26 | Nov 30 | Dec 3 | Dec 7 | Dec 13 | Dec 24 |
| 16°F99% of yrs | Nov 28 | Dec 3 | Dec 7 | Dec 13 | Dec 19 | Dec 25 | Jan 1 | Jan 6 | Jan 15 |
Freeze probabilities 1991–2020 at Hendersonville 1 NE, NC, 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 28790 →Compare Zirconia with another place →
Weather by month in Zirconia
July is the warmest month at Hendersonville 1 NE, NC, averaging 85°F by day and 64°F at night; January is the coldest at 48°F and 27°F. A freezing night is all but certain in every month from November to March (a 90% chance or more). From June to September the chance of a 32°F night stays under 10% each month. In spring, April still brings one in 88% of years and May still brings one in 10% of years.
Warmth for growing adds up to 3,612 growing degree days a year (base 50°F), fewer than at 84% of the 173 North Carolina stations. 37% of them (1,342) have built up by the end of June, and July adds the most, 750. Precipitation totals 59.3 inches a year, most in July (5.8") and least in October (4.1"); May to September bring 44% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 48 | 27 | 5.3 | 100% | 22 | 9 |
| Feb | 52 | 29 | 4.3 | 100% | 18 | 15 |
| Mar | 59 | 35 | 5.0 | 100% | 11 | 69 |
| Apr | 68 | 43 | 4.8 | 88% | 2 | 202 |
| May | 75 | 52 | 4.4 | 10% | 0 | 427 |
| Jun | 82 | 60 | 5.0 | 0% | 0 | 619 |
| Jul | 85 | 64 | 5.8 | 0% | 0 | 750 |
| Aug | 83 | 63 | 5.7 | 0% | 0 | 705 |
| Sep | 78 | 56 | 5.0 | 0% | 0 | 509 |
| Oct | 69 | 45 | 4.1 | 71% | 2 | 231 |
| Nov | 59 | 34 | 4.6 | 100% | 13 | 58 |
| Dec | 51 | 29 | 5.3 | 100% | 20 | 18 |
Monthly normals 1991–2020 at Hendersonville 1 NE, NC (2,160 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, Caesars Head, SC, 11 miles southwest of Zirconia and 1,040 feet higher, has a last frost 4 days earlier (April 10), a first frost 8 days later (November 2), a season 14 days longer.
When it snows in Zirconia, North Carolina
Measurable snow is rare here: only 7 of 24 winters from 1991 to 2020 recorded 0.1 inch or more at Cleveland 3S, SC, 12.2 miles away, so there is no typical first-snow date to plan around.
Planting calendar for 28790
| When | What to do |
|---|---|
| February 3 – February 17 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| February 17 – March 3 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| March 17 – March 31 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| April 14 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by August 2 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by October 11 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| October 25 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 28790 is 9 miles from Hendersonville 1 NE, NC, which stands at 2,160 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 28792 (Hendersonville). The 2023 USDA Plant Hardiness Zone Map lists ZIP 28790 in zone 7b, the band where the coldest night of the year averaged 5 to 10°F (-15.0 to -12.2°C) over 1991–2020; a zone describes winter lows, not frost dates.
Frost dates across North Carolina →
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.