Frost dates for Dearborn #2, MI
At Dearborn #2, the median last spring frost (32°F) is Apr 27 and the median first fall frost is Oct 25, for a typical growing season of 181 days. For a 90% chance that the last frost has passed, wait until May 11. Nearby ZIP codes are in USDA hardiness zone 6b.
- Apr 27Last spring frost (median)50% chance of 32°F after this date
- May 11Safer planting date10% chance of 32°F after this date
- Oct 25First fall frost (median)50% chance of 32°F by this date
- 181 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 25 | May 6 | May 21 |
| 32°F | Apr 12 | Apr 27 | May 11 |
| 28°F | Apr 1 | Apr 15 | Apr 30 |
| 24°F | Mar 18 | Apr 2 | Apr 15 |
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 30 | Oct 13 | Oct 27 |
| 32°F | Oct 10 | Oct 25 | Nov 7 |
| 28°F | Oct 24 | Nov 6 | Nov 21 |
| 24°F | Nov 4 | Nov 19 | Dec 3 |
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 | 138 days | 158 days | 177 days |
| 32°F | 159 days | 181 days | 199 days |
| 28°F | 185 days | 205 days | 224 days |
| 24°F | 210 days | 229 days | 251 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 |
|---|---|---|---|
| 48126 | 6b | -5 to 0°F | 2 km |
| 48204 | 6b | -5 to 0°F | 3 km |
| 48228 | 6b | -5 to 0°F | 4 km |
| 48210 | 6b | -5 to 0°F | 4 km |
| 48227 | 6b | -5 to 0°F | 5 km |
| 48120 | 6b | -5 to 0°F | 5 km |
| 48238 | 6b | -5 to 0°F | 6 km |
| 48206 | 6b | -5 to 0°F | 6 km |
| 48209 | 6b | -5 to 0°F | 6 km |
| 48208 | 6b | -5 to 0°F | 7 km |
| 48217 | 6b | -5 to 0°F | 8 km |
| 48223 | 6b | -5 to 0°F | 8 km |
| 48216 | 6b | -5 to 0°F | 8 km |
| 48235 | 6b | -5 to 0°F | 9 km |
| 48221 | 6b | -5 to 0°F | 9 km |
| 48218 | 6b | -5 to 0°F | 9 km |
| 48233 | 6b | -5 to 0°F | 9 km |
| 48237 | 6b | -5 to 0°F | 13 km |
| 48070 | 6b | -5 to 0°F | 15 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 USC00202016, at 42.3469, -83.1736, elevation 184 m (605 ft).
- Data quality: Representative (10+ years), 14 years of freeze data.
- Average days per year at or below 32°F: 125.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Dearborn (6 km)
- Detroit City Airport (15 km)
- Detroit Metro Airport (18 km)
- Farmington (20 km)
- Grosse Pointe Farms (24 km)
- Detroit Willow Run Airport (32 km)
- Pontiac Wastewater Plant (33 km)
- Carleton 2w (38 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.