Frost dates for Union City, TN
At Union City, the median last spring frost (32°F) is Apr 3 and the median first fall frost is Oct 29, for a typical growing season of 208 days. For a 90% chance that the last frost has passed, wait until Apr 19. Nearby ZIP codes are in USDA hardiness zone 7b.
- Apr 3Last spring frost (median)50% chance of 32°F after this date
- Apr 19Safer planting date10% chance of 32°F after this date
- Oct 29First fall frost (median)50% chance of 32°F by this date
- 208 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 | Mar 30 | Apr 15 | Apr 28 |
| 32°F | Mar 18 | Apr 3 | Apr 19 |
| 28°F | Mar 4 | Mar 22 | Apr 8 |
| 24°F | Feb 18 | Mar 8 | Mar 28 |
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 7 | Oct 19 | Oct 30 |
| 32°F | Oct 17 | Oct 29 | Nov 10 |
| 28°F | Oct 26 | Nov 7 | Nov 26 |
| 24°F | Nov 3 | Nov 20 | Dec 10 |
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 | 169 days | 189 days | 208 days |
| 32°F | 188 days | 208 days | 230 days |
| 28°F | 209 days | 230 days | 256 days |
| 24°F | 230 days | 255 days | 285 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 |
|---|---|---|---|
| 38261 | 7b | 5 to 10°F | 8 km |
| 38253 | 7b | 5 to 10°F | 10 km |
| 38233 | 7b | 5 to 10°F | 21 km |
| 42041 | 7b | 5 to 10°F | 22 km |
| 38259 | 7b | 5 to 10°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 USC00409219, at 36.3925, -89.0317, elevation 107 m (350 ft).
- Data quality: Standard (24+ years of data), 30 years of freeze data.
- Average days per year at or below 32°F: 86.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Martin U Of T Branch E (16 km)
- Samburg Wr (25 km)
- Dresden (32 km)
- Dyersburg III Golf (55 km)
- Dyersburg (55 km)
- Milan Exp. Station (58 km)
- Alamo 1 N (67 km)
- Paris 2 SE (67 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.