| 2023 Hardiness Zone: | Zone 8b: 15°F to 20°F Zone 9a: 20°F to 25°F Zone 8a: 10°F to 15°F | |
| 2012 Hardiness Zone: | Zone 8b: 15°F to 20°F Zone 8a: 10°F to 15°F Zone 7b: 5°F to 10°F | |
| 1990 Hardiness Zone: | Zone 8a: 10F to 15F | |
| Average First Frost Date: | Nov. 1 - Nov. 10 | |
| Average Last Frost Date: | Apr. 21 - Apr. 30 | |
| Koppen-Geiger Climate Zone: | Csb - Warm-Summer Mediterranean Climate | |
| Ecoregion: | 77a - North Cascades Lowland Forests | |
| Current Drought Status: | Exceptional Drought | |
| Heat Zone Days: | Rare Over 86°F |
Annual Climate Data for ZIP Code 98274 - Mount Vernon, WA | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 28 | 30 | 32 | 36 | 41 | 46 | 49 | 49 | 45 | 38 | 33 | 30 | 38 |
| Avg Max Temp (°F) | 40 | 45 | 50 | 57 | 64 | 69 | 74 | 75 | 69 | 58 | 46 | 40 | 57 |
| Avg Precip (In.) | 12.37 | 8.9 | 8.29 | 8.36 | 6.18 | 4.62 | 2.72 | 2.61 | 6.07 | 8.95 | 13.11 | 13.91 | 96.1 |