Last spring frost
Mar 26
Frost Dates for Johnston, SC
First fall frost
Nov 8
Growing season
228 days
Hardiness zone
8a
In an average year around Johnston, SC, the last spring frost (32°F) is about Mar 26 and the first fall frost is about Nov 8, giving roughly a 228-day growing season. To be safe most years, wait until Mar 6 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 22 | Apr 7 | Mar 21 |
| Freeze (32°F) | Apr 11 | Mar 26 | Mar 6 |
| Hard (28°F) | Mar 31 | Mar 13 | Feb 18 |
| Severe (24°F) | Mar 20 | Feb 26 | Jan 30 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Apr 22 | Apr 18 | Apr 13 | Apr 10 | Apr 7 | Apr 4 | Apr 2 | Mar 28 | Mar 21 |
| 32°F | Apr 11 | Apr 6 | Apr 2 | Mar 31 | Mar 26 | Mar 22 | Mar 19 | Mar 14 | Mar 6 |
| 28°F | Mar 31 | Mar 25 | Mar 21 | Mar 16 | Mar 13 | Mar 8 | Mar 4 | Feb 27 | Feb 18 |
| 24°F | Mar 20 | Mar 12 | Mar 6 | Mar 1 | Feb 26 | Feb 20 | Feb 13 | Feb 6 | Jan 30 |
| 20°F | Mar 6 | Feb 27 | Feb 19 | Feb 10 | Feb 4 | Jan 31 | Jan 26 | Jan 16 | Jan 4 |
| 16°F | Feb 23 | Feb 8 | Feb 2 | Jan 31 | Jan 24 | Jan 17 | Jan 13 | Jan 4 | Dec 27 |
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 16 | Oct 29 | Nov 11 |
| Freeze (32°F) | Oct 25 | Nov 8 | Nov 28 |
| Hard (28°F) | Nov 4 | Nov 19 | Dec 12 |
| Severe (24°F) | Nov 14 | Dec 5 | Jan 4 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Oct 16 | Oct 21 | Oct 23 | Oct 26 | Oct 29 | Nov 1 | Nov 3 | Nov 6 | Nov 11 |
| 32°F | Oct 25 | Oct 30 | Nov 2 | Nov 5 | Nov 8 | Nov 11 | Nov 14 | Nov 19 | Nov 28 |
| 28°F | Nov 4 | Nov 8 | Nov 12 | Nov 15 | Nov 19 | Nov 24 | Nov 29 | Dec 4 | Dec 12 |
| 24°F | Nov 14 | Nov 20 | Nov 26 | Dec 1 | Dec 5 | Dec 10 | Dec 20 | Dec 27 | Jan 4 |
| 20°F | Nov 29 | Dec 6 | Dec 13 | Dec 22 | Dec 28 | Jan 1 | Jan 6 | Jan 13 | Jan 25 |
| 16°F | Dec 10 | Dec 21 | Dec 28 | Jan 1 | Jan 8 | Jan 13 | Jan 18 | Jan 26 | Feb 5 |
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: Johnston 4 Sw, Sc, about 5 miles away@if(!empty($station['elevation_ft'])), at 629 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 Johnston, SC?
On average, the last spring frost (32°F) around Johnston, SC is about Mar 26. In cooler years it can run later, so for a safer bet many gardeners wait until Mar 6.
When is the first frost in the fall?
The first fall frost around Johnston, SC typically arrives about Nov 8. 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 26 on average, or Mar 6 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 228 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 29832 Planting calendar → South Carolina frost dates →
Data source: NOAA 1991–2020 Climate Normals · Page updated Aug 4, 2026