Frost dates for Indiana Dunes Nl, IN
At Indiana Dunes Nl, the median last spring frost (32°F) is Apr 22 and the median first fall frost is Oct 27, for a typical growing season of 188 days. For a 90% chance that the last frost has passed, wait until May 8. Nearby ZIP codes are in USDA hardiness zone 6a.
- Apr 22Last spring frost (median)50% chance of 32°F after this date
- May 8Safer planting date10% chance of 32°F after this date
- Oct 27First fall frost (median)50% chance of 32°F by this date
- 188 daysGrowing season (median)between 32°F freezes
Last spring frost dates
The chance that the temperature drops to the threshold after each date.
| Temperature | 90% chance later | 50% chance later | 10% chance later |
|---|---|---|---|
| 36°F | Apr 20 | May 4 | May 21 |
| 32°F | Apr 7 | Apr 22 | May 8 |
| 28°F | Mar 26 | Apr 8 | Apr 23 |
| 24°F | Mar 12 | Mar 29 | Apr 12 |
First fall frost dates
The chance that the temperature has dropped to the threshold by each date.
| Temperature | 10% chance by | 50% chance by | 90% chance by |
|---|---|---|---|
| 36°F | Oct 4 | Oct 16 | Oct 30 |
| 32°F | Oct 15 | Oct 27 | Nov 9 |
| 28°F | Oct 26 | Nov 7 | Nov 25 |
| 24°F | Nov 4 | Nov 19 | Dec 5 |
Growing season length
Days between the last spring and first fall freeze, as the length reached in 9, 5 and 1 out of 10 years.
| Temperature | 9 in 10 years at least | 5 in 10 years at least | 1 in 10 years at least |
|---|---|---|---|
| 36°F | 143 days | 164 days | 184 days |
| 32°F | 167 days | 188 days | 209 days |
| 28°F | 192 days | 213 days | 234 days |
| 24°F | 213 days | 236 days | 258 days |
Chance of a freeze in any year
| Temperature | Chance per year |
|---|---|
| 36°F | 100% |
| 32°F | 100% |
| 28°F | 100% |
| 24°F | 100% |
ZIP codes whose closest station is this one
| ZIP | Hardiness zone | Avg. extreme low | Distance |
|---|---|---|---|
| 46304 | 6a | -10 to -5°F | 4 km |
| 46368 | 6a | -10 to -5°F | 9 km |
| 46301 | 6a | -10 to -5°F | 12 km |
| 46403 | 6a | -10 to -5°F | 14 km |
| 46405 | 6a | -10 to -5°F | 16 km |
| 46402 | 6a | -10 to -5°F | 21 km |
| 46407 | 6a | -10 to -5°F | 21 km |
| 46409 | 6a | -10 to -5°F | 22 km |
| 46404 | 6a | -10 to -5°F | 24 km |
| 46408 | 6a | -10 to -5°F | 25 km |
Not the official USDA Plant Hardiness Zone Map. Zones shown here are the values published in the USDA-ARS / Oregon State University PRISM Group 2023 ZIP code tables, shown unaltered. For the official interactive map, visit planthardiness.ars.usda.gov.
About this station
- NOAA station ID USC00124244, at 41.6317, -87.0881, elevation 207 m (680 ft).
- Data quality: Standard (24+ years of data), 27 years of freeze data.
- Average days per year at or below 32°F: 117.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Valparaiso Wtr Wks (14 km)
- Valparaiso Porter Co Muni Airport (21 km)
- Wanatah 2 WNW (25 km)
- Laporte (30 km)
- Wheatfield (49 km)
- Lowell (49 km)
- Knox Wastewater Plant (53 km)
- South Bend Michiana Regional Airport (65 km)
Sources
- NOAA National Centers for Environmental Information, U.S. Climate Normals 1991–2020, annual/seasonal normals by station (version 1.0.1), file dated June 27, 2023; documentation.
- USDA Agricultural Research Service and PRISM Group, Oregon State University, 2023 Plant Hardiness Zone Map ZIP code tables (CONUS, Alaska, Hawaii, Puerto Rico), files dated November 17, 2023. Data © PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed November 1, 2026. Official map: planthardiness.ars.usda.gov.
- U.S. Census Bureau, 2024 Gazetteer ZIP Code Tabulation Areas file, dated August 30, 2024 (ZIP centroids used to find the nearest station).
Freeze dates are 30-year probabilities, not forecasts. Check your local forecast before planting tender plants.