| 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 Zone 8a: 10°F to 15°F |
| 1990 Hardiness Zone: | Zone 8a: 10F to 15F |
| Average First Frost Date: | Nov. 1 - Nov. 10 |
| Average Last Frost Date: | Apr. 11 - Apr. 20 |
| Koppen-Geiger Climate Zone: | Csb - Warm-Summer Mediterranean Climate |
| Ecoregion: | 3c - Prairie Terraces |
| Heat Zone Days: | Rare Over 86°F |
Annual Climate Data for ZIP Code 97123 - Hillsboro, 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 | 43 | 39 | 35 | 43 |
| Avg Max Temp (°F) | 46 | 51 | 56 | 61 | 68 | 73 | 80 | 81 | 76 | 65 | 52 | 46 | 63 |
| Avg Precip (In.) | 5.99 | 4.91 | 4.11 | 2.63 | 2 | 1.52 | .6 | .9 | 1.6 | 2.86 | 6.14 | 6.52 | 39.76 |