Last spring frost
Mar 25
Frost Dates for Irmo, SC
First fall frost
Nov 7
Growing season
229 days
Hardiness zone
8b
In an average year around Irmo, SC, the last spring frost (32°F) is about Mar 25 and the first fall frost is about Nov 7, giving roughly a 229-day growing season. To be safe most years, wait until Mar 4 before setting out tender plants.
Last spring frost
Dates the last frost of spring typically ends. Plant tender crops after the risk has passed for your comfort level.
| Frost intensity | Early (10%) | Average (50%) | Late (90%) |
|---|---|---|---|
| Light (36°F) | Apr 19 | Apr 5 | Mar 20 |
| Freeze (32°F) | Apr 10 | Mar 25 | Mar 4 |
| Hard (28°F) | Mar 28 | Mar 10 | Feb 14 |
| Severe (24°F) | Mar 15 | Feb 19 | Jan 23 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Apr 19 | Apr 15 | Apr 11 | Apr 8 | Apr 5 | Apr 3 | Mar 31 | Mar 27 | Mar 20 |
| 32°F | Apr 10 | Apr 4 | Apr 1 | Mar 28 | Mar 25 | Mar 21 | Mar 17 | Mar 13 | Mar 4 |
| 28°F | Mar 28 | Mar 22 | Mar 18 | Mar 14 | Mar 10 | Mar 5 | Feb 28 | Feb 23 | Feb 14 |
| 24°F | Mar 15 | Mar 9 | Mar 1 | Feb 25 | Feb 19 | Feb 13 | Feb 7 | Jan 31 | Jan 23 |
| 20°F | Mar 2 | Feb 20 | Feb 11 | Feb 4 | Jan 31 | Jan 26 | Jan 19 | Jan 12 | Dec 31 |
| 16°F | Feb 11 | Feb 3 | Jan 30 | Jan 23 | Jan 19 | Jan 14 | Jan 8 | Jan 1 | Dec 22 |
First fall frost
Dates the first frost of fall typically arrives. Count back by a crop's days-to-maturity to know your planting cutoff.
| Frost intensity | Early (10%) | Average (50%) | Late (90%) |
|---|---|---|---|
| Light (36°F) | Oct 17 | Oct 29 | Nov 11 |
| Freeze (32°F) | Oct 26 | Nov 7 | Nov 24 |
| Hard (28°F) | Nov 4 | Nov 22 | Dec 14 |
| Severe (24°F) | Nov 18 | Dec 7 | Jan 7 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Oct 17 | Oct 22 | Oct 25 | Oct 27 | Oct 29 | Nov 1 | Nov 3 | Nov 6 | Nov 11 |
| 32°F | Oct 26 | Oct 30 | Nov 1 | Nov 4 | Nov 7 | Nov 10 | Nov 14 | Nov 18 | Nov 24 |
| 28°F | Nov 4 | Nov 9 | Nov 14 | Nov 18 | Nov 22 | Nov 26 | Dec 1 | Dec 4 | Dec 14 |
| 24°F | Nov 18 | Nov 25 | Nov 30 | Dec 3 | Dec 7 | Dec 13 | Dec 21 | Dec 30 | Jan 7 |
| 20°F | Dec 1 | Dec 7 | Dec 14 | Dec 22 | Dec 29 | Jan 3 | Jan 8 | Jan 16 | Jan 29 |
| 16°F | Dec 13 | Dec 23 | Dec 30 | Jan 3 | Jan 7 | Jan 12 | Jan 17 | Jan 25 | Feb 3 |
Growing season is measured at 32°F with about 50% probability. Hardiness zone from the 2023 USDA map; frost normals from NOAA 1991-2020.
Where this data comes from
@endif These dates are computed from the nearest official weather station with long-term records: Columbia, Sc, about 10.1 miles away@if(!empty($station['elevation_ft'])), at 231 ft elevation. The further the station and the greater the elevation difference from your yard, the more your local frost timing can vary.
How we calculate these dates
Frost and freeze dates come from the NOAA 1991–2020 U.S. Climate Normals, the National Oceanic and Atmospheric Administration's 30-year averages for each weather station. A date shown at the 50% level is the median: in half of years the frost falls on or before it. The 10% and 90% columns show the early and late ends of the range, so you can plant on the odds you're comfortable with. These are long-term averages, not a forecast for this year - always check your local outlook before planting.
Source: NOAA National Centers for Environmental Information, 1991–2020 Climate Normals (public domain). Harman is not affiliated with or endorsed by NOAA.
Frequently asked questions
When is the last frost in Irmo, SC?
On average, the last spring frost (32°F) around Irmo, SC is about Mar 25. In cooler years it can run later, so for a safer bet many gardeners wait until Mar 4.
When is the first frost in the fall?
The first fall frost around Irmo, SC typically arrives about Nov 7. Count back by a crop's days to maturity to find the latest date you can plant it.
When can I plant tomatoes and other tender crops?
Tender crops like tomatoes, peppers and basil are damaged by frost, so wait until the last spring frost has passed - around Mar 25 on average, or Mar 4 to be safe most years.
How long is the growing season here?
The frost-free growing season (between the last spring and first fall 32°F frost) is about 229 days in a typical year.
Are these dates a forecast for this year?
No. They are 30-year averages from the NOAA 1991–2020 Climate Normals, not a prediction for the current year. Use them for planning and always check your local weather forecast before planting or protecting crops.
Local weather for 29212 Planting calendar → South Carolina frost dates →
Data source: NOAA 1991–2020 Climate Normals · Page updated Aug 4, 2026