USDA Hardiness Zone 8b
Frost Dates for 29063 — Irmo, South Carolina
NOAA 1991–2020 normals from Cedar Creek 2E, SC (338 ft), 10 miles northeast.
Updated
In Irmo, the last spring frost (32°F) is around April 10 in half of years and has passed by April 23 in nine years out of ten. The first fall frost comes around October 28, as early as October 15 one year in ten, leaving a typical freeze-free season of 201 days (NOAA, Cedar Creek 2E, SC).
- Last spring frost
- April 10
- First fall frost
- October 28
- Growing season
- 201 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
- 18%
- Snow per year
- 0.8"
median, 1991–2020
median, 1991–2020
3 of 17 observed
NOAA normal
Frost risk by date in Irmo
Half of springs at Cedar Creek 2E, SC see their last 32°F night by April 10; only one in ten is past it by March 27, and one in ten still has one after April 23. Planting tender crops after April 15 leaves a 30% risk of a frost on them, after April 18 20%, and after April 23 10%. The 13 days between the even-odds date and the one-in-ten date is the narrowest of the 105 South Carolina stations behind this site's ZIP pages.
In fall the first 32°F night comes by October 28 in half of years, as early as October 15 one year in ten, and holds off past November 8 one year in ten. A hard freeze of 28°F follows 8 days later, around November 5; in spring the one-in-ten date for 28°F is April 14, 9 days before the 32°F one. The freeze-free season lasts 201 days in a typical year, shorter than at 96% of the 105 South Carolina stations; it reaches 221 days one year in ten and falls short of 183 one year in ten. On average 95 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 11 days longer, to about April 21, and return around October 20. Severe cold of 16°F or below comes in 95% of winters, usually between December 25 and February 7.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Apr 7 | Apr 12 | Apr 15 | Apr 18 | Apr 21 | Apr 24 | Apr 27 | Apr 30 | May 4 |
| 32°F | Mar 27 | Apr 1 | Apr 4 | Apr 7 | Apr 10 | Apr 12 | Apr 15 | Apr 18 | Apr 23 |
| 28°F | Mar 9 | Mar 18 | Mar 23 | Mar 27 | Mar 31 | Apr 2 | Apr 5 | Apr 9 | Apr 14 |
| 24°F | Feb 21 | Feb 28 | Mar 6 | Mar 12 | Mar 17 | Mar 21 | Mar 25 | Mar 29 | Apr 2 |
| 20°F | Jan 31 | Feb 7 | Feb 16 | Feb 23 | Feb 28 | Mar 5 | Mar 11 | Mar 16 | Mar 24 |
| 16°F95% of yrs | Jan 8 | Jan 20 | Jan 29 | Feb 1 | Feb 7 | Feb 13 | Feb 23 | Mar 3 | Mar 10 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Oct 8 | Oct 12 | Oct 15 | Oct 18 | Oct 20 | Oct 22 | Oct 25 | Oct 27 | Nov 1 |
| 32°F | Oct 15 | Oct 20 | Oct 23 | Oct 25 | Oct 28 | Oct 30 | Nov 1 | Nov 4 | Nov 8 |
| 28°F | Oct 24 | Oct 28 | Nov 1 | Nov 3 | Nov 5 | Nov 8 | Nov 12 | Nov 16 | Nov 23 |
| 24°F | Nov 2 | Nov 7 | Nov 11 | Nov 15 | Nov 18 | Nov 22 | Nov 27 | Dec 2 | Dec 9 |
| 20°F | Nov 14 | Nov 20 | Nov 25 | Dec 1 | Dec 2 | Dec 6 | Dec 11 | Dec 21 | Jan 1 |
| 16°F95% of yrs | Nov 27 | Dec 3 | Dec 9 | Dec 17 | Dec 25 | Jan 1 | Jan 5 | Jan 12 | Jan 23 |
Freeze probabilities 1991–2020 at Cedar Creek 2E, 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 29063 →Compare Irmo with another place →
Weather by month in Irmo
July is the warmest month at Cedar Creek 2E, SC, averaging 90°F by day and 68°F at night; January is the coldest at 54°F and 29°F. A freezing night is all but certain in every month from November to March (a 90% chance or more). From May to September the chance of a 32°F night stays under 10% each month. In spring, April still brings one in 81% of years.
Warmth for growing adds up to 4,723 growing degree days a year (base 50°F), fewer than at 90% of the 105 South Carolina stations. 38% of them (1,817) have built up by the end of June, and July adds the most, 904. Precipitation totals 45.7 inches a year, most in August (5.1") and least in April (2.9"); May to September bring 45% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 54 | 29 | 3.9 | 100% | 22 | 37 |
| Feb | 58 | 31 | 3.5 | 100% | 18 | 44 |
| Mar | 65 | 37 | 4.0 | 98% | 13 | 130 |
| Apr | 74 | 45 | 2.9 | 81% | 4 | 294 |
| May | 81 | 55 | 3.5 | 0% | <1 | 547 |
| Jun | 87 | 64 | 4.1 | 0% | 0 | 765 |
| Jul | 90 | 68 | 4.2 | 0% | 0 | 904 |
| Aug | 88 | 68 | 5.1 | 0% | 0 | 866 |
| Sep | 83 | 60 | 3.8 | 0% | 0 | 649 |
| Oct | 74 | 47 | 3.3 | 64% | 3 | 340 |
| Nov | 64 | 36 | 3.2 | 100% | 15 | 99 |
| Dec | 56 | 31 | 4.2 | 100% | 20 | 48 |
Monthly normals 1991–2020 at Cedar Creek 2E, SC (338 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, Columbia, SC, 13 miles south of Irmo, has a last frost 16 days earlier (March 25), a first frost 10 days later (November 7), a season 28 days longer.
When it snows in Irmo, South Carolina
Measurable snow is rare here: only 3 of 17 winters from 1991 to 2020 recorded 0.1 inch or more at Cedar Creek 2E, SC, 9.6 miles away, so there is no typical first-snow date to plan around.
Planting calendar for 29063
| When | What to do |
|---|---|
| January 30 – February 13 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| February 13 – February 27 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| March 13 – March 27 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| April 10 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by August 5 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by October 14 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| October 28 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 29063 is 10 miles from Cedar Creek 2E, SC, which stands at 338 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 1 other ZIP code shares the station. The 2023 USDA Plant Hardiness Zone Map lists ZIP 29063 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.