| 2023 Hardiness Zone: | Zone 8b: 15°F to 20°F Zone 9a: 20°F to 25°F |
| 2012 Hardiness Zone: | Zone 8b: 15°F to 20°F |
| 1990 Hardiness Zone: | Zone 8b: 15F to 20F |
| Average First Frost Date: | Nov. 1 - Nov. 10 |
| Average Last Frost Date: | Apr. 1 - Apr. 10 |
| Koppen-Geiger Climate Zone: | Csb - Warm-Summer Mediterranean Climate |
| Ecoregion: | 3a - Portland/Vancouver Basin |
| Heat Zone Days: | Rare Over 86°F |
Annual Climate Data for ZIP Code 97030 - Gresham, OR | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 34 | 36 | 38 | 41 | 46 | 51 | 54 | 54 | 50 | 44 | 39 | 35 | 44 |
| Avg Max Temp (°F) | 46 | 51 | 56 | 61 | 68 | 74 | 80 | 81 | 76 | 64 | 52 | 46 | 63 |
| Avg Precip (In.) | 6.96 | 5.66 | 5.04 | 3.92 | 3.11 | 2.29 | .94 | 1.2 | 2.17 | 3.93 | 7.18 | 7.51 | 49.91 |