Frost dates for Klamath Falls Intl Airport, OR
At Klamath Falls Intl Airport, the median last spring frost (32°F) is Jun 9 and the median first fall frost is Sep 18, for a typical growing season of 99 days. For a 90% chance that the last frost has passed, wait until Jun 26. Nearby ZIP codes are in USDA hardiness zones 6a to 6b.
- Jun 9Last spring frost (median)50% chance of 32°F after this date
- Jun 26Safer planting date10% chance of 32°F after this date
- Sep 18First fall frost (median)50% chance of 32°F by this date
- 99 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 |
|---|---|---|---|
| 32°F | May 22 | Jun 9 | Jun 26 |
| 28°F | May 2 | May 21 | Jun 12 |
| 24°F | Apr 13 | May 1 | May 20 |
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 |
|---|---|---|---|
| 32°F | Sep 4 | Sep 18 | Oct 1 |
| 28°F | Sep 17 | Oct 2 | Oct 17 |
| 24°F | Oct 2 | Oct 17 | Nov 1 |
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 | 45 days | 72 days | 91 days |
| 32°F | 77 days | 99 days | 120 days |
| 28°F | 106 days | 132 days | 158 days |
| 24°F | 143 days | 168 days | 191 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 |
|---|---|---|---|
| 97603 | 6b | -5 to 0°F | 5 km |
| 97634 | 6b | -5 to 0°F | 7 km |
| 97625 | 6b | -5 to 0°F | 22 km |
| 97639 | 6a | -10 to -5°F | 37 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 USW00094236, at 42.1469, -121.7242, elevation 1245 m (4,084 ft).
- Data quality: Representative (10+ years), 21 years of freeze data.
- Average days per year at or below 32°F: 184.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Keno (16 km)
- Gerber Dam (49 km)
- Howard Prairie Dam (55 km)
- Chiloquin 12 NW (fort Klamath) (66 km)
- Ashland (82 km)
- Crater Lake NPS HQ (90 km)
- Prospect 2 SW (92 km)
- Bly 4 SE (95 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.