Frost dates for Plymouth, IN
At Plymouth, the median last spring frost (32°F) is Apr 25 and the median first fall frost is Oct 21, for a typical growing season of 178 days. For a 90% chance that the last frost has passed, wait until May 13. Nearby ZIP codes are in USDA hardiness zone 6a.
- Apr 25Last spring frost (median)50% chance of 32°F after this date
- May 13Safer planting date10% chance of 32°F after this date
- Oct 21First fall frost (median)50% chance of 32°F by this date
- 178 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 22 | May 6 | May 23 |
| 32°F | Apr 12 | Apr 25 | May 13 |
| 28°F | Mar 31 | Apr 14 | Apr 30 |
| 24°F | Mar 18 | Apr 2 | Apr 16 |
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 | Sep 27 | Oct 9 | Oct 24 |
| 32°F | Oct 5 | Oct 21 | Nov 3 |
| 28°F | Oct 19 | Nov 1 | Nov 15 |
| 24°F | Nov 1 | Nov 12 | Nov 30 |
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 | 132 days | 154 days | 174 days |
| 32°F | 156 days | 178 days | 197 days |
| 28°F | 180 days | 200 days | 220 days |
| 24°F | 203 days | 222 days | 245 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 |
|---|---|---|---|
| 46563 | 6a | -10 to -5°F | 2 km |
| 46572 | 6a | -10 to -5°F | 9 km |
| 46513 | 6a | -10 to -5°F | 10 km |
| 46501 | 6a | -10 to -5°F | 15 km |
| 46511 | 6a | -10 to -5°F | 15 km |
| 46504 | 6a | -10 to -5°F | 19 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 USC00126989, at 41.3392, -86.3358, elevation 248 m (815 ft).
- Data quality: Standard (24+ years of data), 26 years of freeze data.
- Average days per year at or below 32°F: 132.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Lakeville (22 km)
- Knox Wastewater Plant (25 km)
- Rochester (32 km)
- Warsaw (40 km)
- Winamac 2sse (41 km)
- S Bend (41 km)
- South Bend Michiana Regional Airport (41 km)
- Laporte (45 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.