Frost dates for Portland Kgw-Tv, OR
At Portland Kgw-Tv, the median last spring frost (32°F) is Feb 25 and the median first fall frost is Dec 1, for a typical growing season of 280 days. For a 90% chance that the last frost has passed, wait until Mar 21. Nearby ZIP codes are in USDA hardiness zones 8b to 9a.
- Feb 25Last spring frost (median)50% chance of 32°F after this date
- Mar 21Safer planting date10% chance of 32°F after this date
- Dec 1First fall frost (median)50% chance of 32°F by this date
- 280 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 7 | Mar 29 | Apr 21 |
| 32°F | Jan 24 | Feb 25 | Mar 21 |
| 28°F | Dec 21 | Jan 31 | Feb 26 |
| 24°F | Dec 8 | Jan 15 | Feb 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 | Oct 28 | Nov 12 | Dec 1 |
| 32°F | Nov 10 | Dec 1 | Dec 27 |
| 28°F | Nov 25 | Dec 20 | Jan 30 |
| 24°F | Nov 30 | Dec 29 | Feb 11 |
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 | 200 days | 227 days | 258 days |
| 32°F | 245 days | 280 days | 318 days |
| 28°F | 292 days | 329 days | 365 days |
| 24°F | 319 days | 363 days | 365 days |
Chance of a freeze in any year
| Temperature | Chance per year |
|---|---|
| 36°F | 100% |
| 32°F | 100% |
| 28°F | 86% |
| 24°F | 49% |
ZIP codes whose closest station is this one
| ZIP | Hardiness zone | Avg. extreme low | Distance |
|---|---|---|---|
| 97205 | 8b | 15 to 20°F | 1 km |
| 97201 | 8b | 15 to 20°F | 1 km |
| 97204 | 9a | 20 to 25°F | 1 km |
| 97208 | 9a | 20 to 25°F | 1 km |
| 97209 | 9a | 20 to 25°F | 2 km |
| 97227 | 9a | 20 to 25°F | 3 km |
| 97239 | 8b | 15 to 20°F | 3 km |
| 97214 | 9a | 20 to 25°F | 4 km |
| 97232 | 9a | 20 to 25°F | 4 km |
| 97221 | 8b | 15 to 20°F | 4 km |
| 97212 | 8b | 15 to 20°F | 5 km |
| 97210 | 8b | 15 to 20°F | 5 km |
| 97202 | 9a | 20 to 25°F | 5 km |
| 97219 | 8b | 15 to 20°F | 7 km |
| 97206 | 9a | 20 to 25°F | 8 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 USC00356749, at 45.5181, -122.6894, elevation 48 m (159 ft).
- Data quality: Representative (10+ years), 24 years of freeze data.
- Average days per year at or below 32°F: 18.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Portland Intl Airport (11 km)
- Nature Park-Beaverton (12 km)
- Beaverton 2 SSW (12 km)
- Portland WFO (13 km)
- Oregon City (19 km)
- Portland-Hillsboro Airport (20 km)
- Portland Troutdale Airport (22 km)
- Troutdale (24 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.