USDA Hardiness Zone 8b
Frost Dates for 29812 — Barnwell, South Carolina
NOAA 1991–2020 normals from Barnwell 5 ENE, SC (245 ft), 7 miles east.
Updated
In Barnwell, the last spring frost (32°F) is around March 22 in half of years and has passed by April 9 in nine years out of ten. The first fall frost comes around November 9, as early as October 30 one year in ten, leaving a typical freeze-free season of 233 days (NOAA, Barnwell 5 ENE, SC).
- Last spring frost
- March 22
- First fall frost
- November 9
- Growing season
- 233 days
- Hardiness zone
- 8b
50% probability
50% probability
freeze-free, 50%
15 to 20°F (-9.4 to -6.7°C) coldest night
- First snow
- Rare
- Last snow
- Rare
- Winters with snow
- 11%
- Snow per year
- —
median, 1991–2020
median, 1991–2020
2 of 19 observed
NOAA normal
Frost risk by date in Barnwell
Half of springs at Barnwell 5 ENE, SC see their last 32°F night by March 22; only one in ten is past it by March 1, and one in ten still has one after April 9. Planting tender crops after March 30 leaves a 30% risk of a frost on them, after April 3 20%, and after April 9 10%. The 18 days between the even-odds date and the one-in-ten date is wider than at 77% of the 105 South Carolina stations behind this site's ZIP pages.
In fall the first 32°F night comes by November 9 in half of years, as early as October 30 one year in ten, and holds off past November 25 one year in ten. A hard freeze of 28°F follows 11 days later, around November 20; in spring the one-in-ten date for 28°F is March 27, 13 days before the 32°F one. The freeze-free season lasts 233 days in a typical year, longer than at 54% of the 105 South Carolina stations; it reaches 259 days one year in ten and falls short of 210 one year in ten. On average 50 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 4, and return around November 1. Nights of 24°F, cold enough to damage hardier plants, come in 99% of winters and 16°F in 50%.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Mar 19 | Mar 24 | Mar 29 | Apr 1 | Apr 4 | Apr 7 | Apr 11 | Apr 15 | Apr 20 |
| 32°F | Mar 1 | Mar 9 | Mar 15 | Mar 18 | Mar 22 | Mar 26 | Mar 30 | Apr 3 | Apr 9 |
| 28°F | Feb 11 | Feb 21 | Feb 28 | Mar 4 | Mar 8 | Mar 13 | Mar 18 | Mar 22 | Mar 27 |
| 24°F99% of yrs | Jan 19 | Jan 30 | Feb 3 | Feb 10 | Feb 17 | Feb 26 | Mar 2 | Mar 10 | Mar 17 |
| 20°F85% of yrs | Dec 30 | Jan 12 | Jan 19 | Jan 27 | Jan 31 | Feb 4 | Feb 11 | Feb 21 | Mar 4 |
| 16°F50% of yrs | Dec 25 | Jan 3 | Jan 10 | Jan 15 | Jan 21 | Jan 27 | Jan 31 | Feb 5 | Feb 16 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Oct 20 | Oct 25 | Oct 28 | Oct 31 | Nov 1 | Nov 4 | Nov 6 | Nov 9 | Nov 14 |
| 32°F | Oct 30 | Nov 1 | Nov 4 | Nov 7 | Nov 9 | Nov 12 | Nov 15 | Nov 19 | Nov 25 |
| 28°F | Nov 6 | Nov 10 | Nov 14 | Nov 17 | Nov 20 | Nov 24 | Nov 30 | Dec 5 | Dec 16 |
| 24°F99% of yrs | Nov 16 | Nov 22 | Nov 27 | Dec 2 | Dec 7 | Dec 18 | Dec 27 | Jan 3 | Jan 12 |
| 20°F85% of yrs | Nov 28 | Dec 6 | Dec 16 | Dec 26 | Jan 1 | Jan 6 | Jan 12 | Jan 17 | Feb 1 |
| 16°F50% of yrs | Dec 13 | Dec 24 | Jan 1 | Jan 5 | Jan 10 | Jan 14 | Jan 20 | Jan 28 | Feb 4 |
Freeze probabilities 1991–2020 at Barnwell 5 ENE, SC, 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 29812 →Compare Barnwell with another place →
Weather by month in Barnwell
July is the warmest month at Barnwell 5 ENE, SC, averaging 93°F by day and 71°F at night; January is the coldest at 59°F and 35°F. A freezing night is all but certain in every month from November to February (a 90% chance or more). From May to September the chance of a 32°F night stays under 10% each month. In spring, March still brings one in 88% of years and April still brings one in 26% of years.
Warmth for growing adds up to 5,917 growing degree days a year (base 50°F), more than at 81% of the 105 South Carolina stations. 41% of them (2,422) have built up by the end of June, and July adds the most, 989. Precipitation totals 49.0 inches a year, most in July (5.6") and least in November (2.8"); May to September bring 50% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 59 | 35 | 3.8 | 100% | 16 | 86 |
| Feb | 63 | 37 | 3.9 | 97% | 10 | 112 |
| Mar | 70 | 43 | 4.2 | 88% | 6 | 242 |
| Apr | 78 | 50 | 3.1 | 26% | <1 | 426 |
| May | 85 | 59 | 3.6 | 0% | 0 | 693 |
| Jun | 90 | 67 | 5.5 | 0% | 0 | 864 |
| Jul | 93 | 71 | 5.6 | 0% | 0 | 989 |
| Aug | 92 | 70 | 5.3 | 0% | 0 | 955 |
| Sep | 87 | 64 | 4.3 | 0% | 0 | 762 |
| Oct | 78 | 53 | 3.1 | 14% | <1 | 487 |
| Nov | 69 | 41 | 2.8 | 94% | 7 | 195 |
| Dec | 61 | 37 | 3.8 | 98% | 11 | 108 |
Monthly normals 1991–2020 at Barnwell 5 ENE, SC (245 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, Blackville 3 W, SC, 9 miles north of Barnwell, has a last frost 2 days earlier (March 20), a first frost 4 days later (November 13), a season 5 days longer.
When it snows in Barnwell, South Carolina
Measurable snow is rare here: only 2 of 19 winters from 1991 to 2020 recorded 0.1 inch or more at Allendale 2 NW, SC, 14.7 miles away, so there is no typical first-snow date to plan around.
Planting calendar for 29812
| When | What to do |
|---|---|
| January 11 – January 25 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| January 25 – February 8 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| February 22 – March 8 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| March 22 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by August 17 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by October 26 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| November 9 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 29812 is 7 miles from Barnwell 5 ENE, SC, which stands at 245 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 29812 in zone 8b, the band where the coldest night of the year averaged 15 to 20°F (-9.4 to -6.7°C) over 1991–2020; a zone describes winter lows, not frost dates.
Frost dates across South 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.