Frost dates for Alkali Lake, OR
At Alkali Lake, the median last spring frost (32°F) is Jun 10 and the median first fall frost is Sep 14, for a typical growing season of 94 days. For a 90% chance that the last frost has passed, wait until Jun 27. Nearby ZIP codes are in USDA hardiness zones 6a to 6b.
- Jun 10Last spring frost (median)50% chance of 32°F after this date
- Jun 27Safer planting date10% chance of 32°F after this date
- Sep 14First fall frost (median)50% chance of 32°F by this date
- 94 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 21 | Jun 10 | Jun 27 |
| 28°F | May 5 | May 21 | Jun 12 |
| 24°F | Apr 21 | May 4 | May 22 |
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 | Aug 31 | Sep 14 | Sep 25 |
| 28°F | Sep 11 | Sep 25 | Oct 8 |
| 24°F | Sep 24 | Oct 5 | Oct 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 | 44 days | 67 days | 88 days |
| 32°F | 72 days | 94 days | 116 days |
| 28°F | 99 days | 124 days | 146 days |
| 24°F | 131 days | 153 days | 174 days |
Chance of a freeze in any year
| Temperature | Chance per year |
|---|---|
| 36°F | 100% |
| 32°F | 100% |
| 28°F | 100% |
| 24°F | 100% |
Closest ZIP codes (each is closer to another station)
| ZIP | Hardiness zone | Avg. extreme low | Distance |
|---|---|---|---|
| 97640 | 6b | -5 to 0°F | 44 km |
| 97637 | 6b | -5 to 0°F | 55 km |
| 97641 | 6a | -10 to -5°F | 56 km |
| 97758 | 6a | -10 to -5°F | 57 km |
| 97636 | 6b | -5 to 0°F | 59 km |
| 97620 | 6b | -5 to 0°F | 77 km |
| 97630 | 6b | -5 to 0°F | 81 km |
| 97638 | 6a | -10 to -5°F | 86 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 USC00350118, at 42.9694, -119.9933, elevation 1320 m (4,332 ft).
- Data quality: Representative (10+ years), 11 years of freeze data.
- Average days per year at or below 32°F: 201.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Paisley (54 km)
- Hart Mountain Refuge (54 km)
- Riley 10 WSW (61 km)
- Squaw Butte-Northern Great Bas (62 km)
- Summer Lake 1 S (65 km)
- O O Rch (65 km)
- The Poplars (84 km)
- Lakeview 2 NNW (87 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.