Last spring frost
Apr 23
Frost Dates for Rensselaer, IN
First fall frost
Oct 18
Growing season
177 days
Hardiness zone
6a
In an average year around Rensselaer, IN, the last spring frost (32°F) is about Apr 23 and the first fall frost is about Oct 18, giving roughly a 177-day growing season. To be safe most years, wait until Apr 9 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 19 | May 4 | Apr 21 |
| Freeze (32°F) | May 7 | Apr 23 | Apr 9 |
| Hard (28°F) | Apr 27 | Apr 11 | Mar 29 |
| Severe (24°F) | Apr 16 | Apr 1 | Mar 14 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | May 19 | May 14 | May 10 | May 6 | May 4 | May 1 | Apr 29 | Apr 25 | Apr 21 |
| 32°F | May 7 | May 1 | Apr 29 | Apr 26 | Apr 23 | Apr 20 | Apr 17 | Apr 13 | Apr 9 |
| 28°F | Apr 27 | Apr 21 | Apr 17 | Apr 15 | Apr 11 | Apr 8 | Apr 5 | Apr 3 | Mar 29 |
| 24°F | Apr 16 | Apr 10 | Apr 6 | Apr 3 | Apr 1 | Mar 29 | Mar 26 | Mar 20 | Mar 14 |
| 20°F | Apr 5 | Mar 31 | Mar 28 | Mar 23 | Mar 20 | Mar 16 | Mar 13 | Mar 8 | Mar 2 |
| 16°F | Mar 26 | Mar 20 | Mar 16 | Mar 13 | Mar 9 | Mar 6 | Mar 2 | Feb 27 | Feb 20 |
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 25 | Oct 7 | Oct 20 |
| Freeze (32°F) | Oct 4 | Oct 18 | Nov 1 |
| Hard (28°F) | Oct 16 | Oct 29 | Nov 11 |
| Severe (24°F) | Oct 29 | Nov 9 | Nov 26 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 25 | Sep 30 | Oct 3 | Oct 5 | Oct 7 | Oct 10 | Oct 12 | Oct 15 | Oct 20 |
| 32°F | Oct 4 | Oct 9 | Oct 13 | Oct 16 | Oct 18 | Oct 20 | Oct 23 | Oct 27 | Nov 1 |
| 28°F | Oct 16 | Oct 21 | Oct 24 | Oct 27 | Oct 29 | Nov 1 | Nov 3 | Nov 6 | Nov 11 |
| 24°F | Oct 29 | Nov 1 | Nov 3 | Nov 6 | Nov 9 | Nov 11 | Nov 15 | Nov 19 | Nov 26 |
| 20°F | Nov 6 | Nov 10 | Nov 13 | Nov 17 | Nov 21 | Nov 24 | Nov 28 | Dec 2 | Dec 8 |
| 16°F | Nov 13 | Nov 19 | Nov 23 | Nov 26 | Nov 30 | Dec 3 | Dec 7 | Dec 12 | Dec 19 |
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: Rensselaer, In, about 5.4 miles away@if(!empty($station['elevation_ft'])), at 630 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 Rensselaer, IN?
On average, the last spring frost (32°F) around Rensselaer, IN is about Apr 23. In cooler years it can run later, so for a safer bet many gardeners wait until Apr 9.
When is the first frost in the fall?
The first fall frost around Rensselaer, IN typically arrives about Oct 18. 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 23 on average, or Apr 9 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 177 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 47978 Planting calendar → Indiana frost dates →
Data source: NOAA 1991–2020 Climate Normals · Page updated Aug 4, 2026