Frost dates for Portland 1 SW, IN
At Portland 1 SW, the median last spring frost (32°F) is Apr 28 and the median first fall frost is Oct 15, for a typical growing season of 171 days. For a 90% chance that the last frost has passed, wait until May 14. Nearby ZIP codes are in USDA hardiness zone 6a.
- Apr 28Last spring frost (median)50% chance of 32°F after this date
- May 14Safer planting date10% chance of 32°F after this date
- Oct 15First fall frost (median)50% chance of 32°F by this date
- 171 daysGrowing season (median)between 32°F freezes
USDA hardiness zone 6a (-10 to -5°F) · see all zone 6a frost dates
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 24 | May 7 | May 21 |
| 32°F | Apr 13 | Apr 28 | May 14 |
| 28°F | Apr 1 | Apr 15 | May 2 |
| 24°F | Mar 18 | Apr 3 | Apr 18 |
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 23 | Oct 5 | Oct 18 |
| 32°F | Oct 1 | Oct 15 | Oct 30 |
| 28°F | Oct 11 | Oct 28 | Nov 10 |
| 24°F | Oct 22 | Nov 5 | Nov 24 |
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 | 151 days | 170 days |
| 32°F | 150 days | 171 days | 192 days |
| 28°F | 171 days | 194 days | 215 days |
| 24°F | 195 days | 217 days | 239 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 |
|---|---|---|---|
| 47371 | 6a | -10 to -5°F | 3 km |
| 47381 | 6a | -10 to -5°F | 11 km |
| 45846 | 6a | -10 to -5°F | 21 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 USC00127069, at 40.4175, -84.9925, elevation 277 m (910 ft).
- Data quality: Representative (10+ years), 24 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
- Farmland 5 NNW (22 km)
- Hartford City 4 ESE (25 km)
- Winchester Airport 3 E (28 km)
- Berne Wastewater Plant (28 km)
- Muncie Delaware Co Airport (40 km)
- Bluffton 6N (46 km)
- Decatur 1 N (48 km)
- Marion 2 N (59 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.