USDA Hardiness Zone 7a
Frost Dates for 28640 — Jefferson, North Carolina
NOAA 1991–2020 normals from Jefferson 2 E, NC (2,759 ft), under a mile northwest.
Updated
In Jefferson, the last spring frost (32°F) is around May 7 in half of years and has passed by May 24 in nine years out of ten. The first fall frost comes around October 8, as early as September 25 one year in ten, leaving a typical freeze-free season of 154 days (NOAA, Jefferson 2 E, NC).
- Last spring frost
- May 7
- First fall frost
- October 8
- Growing season
- 154 days
- Hardiness zone
- 7a
50% probability
50% probability
freeze-free, 50%
0 to 5°F (-17.8 to -15.0°C) coldest night
- First snow
- December 9
- Last snow
- February 26
- Winters with snow
- 81%
- Snow per year
- 14.4"
median, 1991–2020
median, 1991–2020
21 of 26 observed
NOAA normal
Frost risk by date in Jefferson
Half of springs at Jefferson 2 E, NC see their last 32°F night by May 7; only one in ten is past it by April 22, and one in ten still has one after May 24. Planting tender crops after May 14 leaves a 30% risk of a frost on them, after May 19 20%, and after May 24 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 8 in half of years, as early as September 25 one year in ten, and holds off past October 22 one year in ten. A hard freeze of 28°F follows 10 days later, around October 18; in spring the one-in-ten date for 28°F is May 13, 11 days before the 32°F one. The freeze-free season lasts 154 days in a typical year, the shortest of the 173 North Carolina stations; it reaches 175 days one year in ten and falls short of 134 one year in ten. On average 136 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 12 days longer, to about May 19, and return around September 30. Severe cold of 16°F or below comes every winter, usually between November 20 and March 12.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | May 3 | May 8 | May 12 | May 16 | May 19 | May 22 | May 26 | May 30 | Jun 3 |
| 32°F | Apr 22 | Apr 27 | May 1 | May 4 | May 7 | May 11 | May 14 | May 19 | May 24 |
| 28°F | Apr 8 | Apr 13 | Apr 17 | Apr 21 | Apr 25 | Apr 29 | May 3 | May 7 | May 13 |
| 24°F | Mar 26 | Mar 31 | Apr 3 | Apr 7 | Apr 11 | Apr 13 | Apr 17 | Apr 22 | May 1 |
| 20°F | Mar 9 | Mar 16 | Mar 21 | Mar 25 | Mar 28 | Mar 31 | Apr 2 | Apr 8 | Apr 13 |
| 16°F | Feb 16 | Feb 27 | Mar 4 | Mar 8 | Mar 12 | Mar 17 | Mar 21 | Mar 27 | Mar 31 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 14 | Sep 20 | Sep 24 | Sep 28 | Sep 30 | Oct 2 | Oct 5 | Oct 8 | Oct 12 |
| 32°F | Sep 25 | Oct 1 | Oct 3 | Oct 6 | Oct 8 | Oct 11 | Oct 14 | Oct 17 | Oct 22 |
| 28°F | Oct 6 | Oct 10 | Oct 13 | Oct 16 | Oct 18 | Oct 21 | Oct 24 | Oct 27 | Nov 1 |
| 24°F | Oct 13 | Oct 18 | Oct 22 | Oct 25 | Oct 28 | Oct 31 | Nov 2 | Nov 5 | Nov 11 |
| 20°F | Oct 24 | Oct 29 | Nov 1 | Nov 4 | Nov 6 | Nov 9 | Nov 13 | Nov 18 | Nov 26 |
| 16°F | Nov 3 | Nov 8 | Nov 12 | Nov 16 | Nov 20 | Nov 25 | Nov 30 | Dec 4 | Dec 12 |
Freeze probabilities 1991–2020 at Jefferson 2 E, 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 28640 →Compare Jefferson with another place →
Weather by month in Jefferson
July is the warmest month at Jefferson 2 E, NC, averaging 81°F by day and 58°F at night; January is the coldest at 43°F and 22°F. A freezing night is all but certain in every month from October to April (a 90% chance or more). From June to August the chance of a 32°F night stays under 10% each month. In spring, May still brings one in 70% of years.
Warmth for growing adds up to 2,608 growing degree days a year (base 50°F), fewer than at 97% of the 173 North Carolina stations. 34% of them (881) have built up by the end of June, and July adds the most, 604. Precipitation totals 51.0 inches a year, most in May (5.3") and least in February (3.3"); May to September bring 46% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 43 | 22 | 3.9 | 100% | 26 | 4 |
| Feb | 47 | 24 | 3.3 | 100% | 23 | 6 |
| Mar | 54 | 29 | 4.1 | 100% | 20 | 28 |
| Apr | 63 | 36 | 4.8 | 100% | 10 | 98 |
| May | 71 | 45 | 5.3 | 70% | 3 | 274 |
| Jun | 78 | 53 | 4.4 | 1% | 0 | 471 |
| Jul | 81 | 58 | 4.8 | 0% | 0 | 604 |
| Aug | 80 | 57 | 4.7 | 0% | 0 | 570 |
| Sep | 75 | 50 | 4.4 | 19% | 1 | 386 |
| Oct | 66 | 39 | 3.7 | 98% | 9 | 133 |
| Nov | 55 | 29 | 3.6 | 100% | 21 | 26 |
| Dec | 47 | 25 | 4.0 | 100% | 25 | 8 |
Monthly normals 1991–2020 at Jefferson 2 E, NC (2,759 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, Sparta 3.5 SSW, NC, 15 miles east of Jefferson and 252 feet higher, has a last frost 15 days earlier (April 22), a first frost 14 days later (October 22), a season 26 days longer.
When it snows in Jefferson, North Carolina
The first measurable snow (0.1 inch or more) in Jefferson usually arrives around December 9, and the last of the season around February 26. Those are the middle dates across the winters of 1991–2020 at Jefferson 2 E, NC, 0.6 miles away: half of years saw snow earlier, half later. Snow fell in 81% of those winters. The last 32°F night of spring typically comes 70 days after the last snow.
Planting calendar for 28640
| When | What to do |
|---|---|
| February 26 – March 12 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| March 12 – March 26 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| April 9 – April 23 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| May 7 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by July 16 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by September 24 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| October 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 28640 is under a mile from Jefferson 2 E, NC, which stands at 2,759 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 2 other ZIP codes share the station; its figures are presented in full for 28694 (West Jefferson). The 2023 USDA Plant Hardiness Zone Map lists ZIP 28640 in zone 7a, the band where the coldest night of the year averaged 0 to 5°F (-17.8 to -15.0°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.