| 2023 Hardiness Zone: | Zone 8b: 15°F to 20°F |
| 2012 Hardiness Zone: | Zone 8b: 15°F to 20°F Zone 8a: 10°F to 15°F |
| 1990 Hardiness Zone: | Zone 8b: 15F to 20F |
| Average First Frost Date: | Oct. 21 - Oct. 31 |
| Average Last Frost Date: | Apr. 21 - Apr. 30 |
| 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 97361 - Monmouth, OR | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 33 | 35 | 37 | 39 | 44 | 48 | 51 | 51 | 47 | 41 | 38 | 34 | 41 |
| Avg Max Temp (°F) | 46 | 51 | 56 | 61 | 68 | 74 | 81 | 82 | 77 | 65 | 52 | 46 | 63 |
| Avg Precip (In.) | 7.95 | 6.53 | 5.36 | 3.19 | 2.22 | 1.39 | .48 | .64 | 1.44 | 3.4 | 7.46 | 8.71 | 48.77 |