Last spring frost
Apr 27
Frost Dates for Sulphur Springs, IN
First fall frost
Oct 17
Growing season
173 days
Hardiness zone
6a
In an average year around Sulphur Springs, IN, the last spring frost (32°F) is about Apr 27 and the first fall frost is about Oct 17, giving roughly a 173-day growing season. To be safe most years, wait until Apr 11 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) | May 21 | May 6 | Apr 21 |
| Freeze (32°F) | May 12 | Apr 27 | Apr 11 |
| Hard (28°F) | May 3 | Apr 15 | Mar 31 |
| Severe (24°F) | Apr 19 | Apr 2 | Mar 18 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | May 21 | May 16 | May 12 | May 9 | May 6 | May 3 | Apr 30 | Apr 26 | Apr 21 |
| 32°F | May 12 | May 7 | May 3 | Apr 30 | Apr 27 | Apr 23 | Apr 19 | Apr 16 | Apr 11 |
| 28°F | May 3 | Apr 28 | Apr 22 | Apr 18 | Apr 15 | Apr 11 | Apr 6 | Apr 3 | Mar 31 |
| 24°F | Apr 19 | Apr 14 | Apr 8 | Apr 5 | Apr 2 | Mar 31 | Mar 28 | Mar 23 | Mar 18 |
| 20°F | Apr 7 | Apr 2 | Mar 31 | Mar 27 | Mar 24 | Mar 20 | Mar 16 | Mar 13 | Mar 7 |
| 16°F | Mar 30 | Mar 24 | Mar 20 | Mar 16 | Mar 14 | Mar 11 | Mar 7 | Mar 3 | Feb 25 |
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) | Sep 24 | Oct 7 | Oct 18 |
| Freeze (32°F) | Oct 4 | Oct 17 | Oct 28 |
| Hard (28°F) | Oct 13 | Oct 27 | Nov 8 |
| Severe (24°F) | Oct 23 | Nov 6 | Nov 25 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 24 | Sep 29 | Oct 1 | Oct 4 | Oct 7 | Oct 9 | Oct 12 | Oct 14 | Oct 18 |
| 32°F | Oct 4 | Oct 9 | Oct 12 | Oct 14 | Oct 17 | Oct 19 | Oct 21 | Oct 25 | Oct 28 |
| 28°F | Oct 13 | Oct 18 | Oct 21 | Oct 24 | Oct 27 | Oct 29 | Nov 1 | Nov 4 | Nov 8 |
| 24°F | Oct 23 | Oct 29 | Nov 1 | Nov 3 | Nov 6 | Nov 9 | Nov 13 | Nov 17 | Nov 25 |
| 20°F | Nov 3 | Nov 7 | Nov 12 | Nov 16 | Nov 19 | Nov 24 | Nov 29 | Dec 3 | Dec 9 |
| 16°F | Nov 13 | Nov 19 | Nov 23 | Nov 28 | Dec 1 | Dec 4 | Dec 8 | Dec 14 | Dec 21 |
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: New Castle 3 Sw, In, about 8.1 miles away@if(!empty($station['elevation_ft'])), at 991 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 Sulphur Springs, IN?
On average, the last spring frost (32°F) around Sulphur Springs, IN is about Apr 27. In cooler years it can run later, so for a safer bet many gardeners wait until Apr 11.
When is the first frost in the fall?
The first fall frost around Sulphur Springs, IN typically arrives about Oct 17. 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 Apr 27 on average, or Apr 11 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 173 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 47388 Planting calendar → Indiana frost dates →
Data source: NOAA 1991–2020 Climate Normals · Page updated Aug 4, 2026