| 2023 Hardiness Zone: | Zone 8b: 15°F to 20°F Zone 8a: 10°F to 15°F |
| 2012 Hardiness Zone: | Zone 8a: 10°F to 15°F Zone 7b: 5°F to 10°F Zone 7a: 0°F to 5°F |
| 1990 Hardiness Zone: | Zone 8a: 10F to 15F |
| Average First Frost Date: | Oct. 21 - Oct. 31 |
| Average Last Frost Date: | Apr. 11 - Apr. 20 |
| Koppen-Geiger Climate Zone: | Cfb - Oceanic Climate |
| Ecoregion: | 2a - Fraser Lowland |
| Heat Zone Days: | Rare Over 86°F |
Annual Climate Data for ZIP Code 98295 - Sumas, WA | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 32 | 34 | 37 | 40 | 45 | 49 | 52 | 51 | 47 | 42 | 37 | 32 | 41 |
| Avg Max Temp (°F) | 42 | 47 | 52 | 58 | 65 | 69 | 74 | 75 | 70 | 59 | 48 | 43 | 59 |
| Avg Precip (In.) | 6.18 | 5.09 | 4.73 | 4.03 | 3.51 | 2.9 | 1.95 | 1.75 | 2.74 | 4.99 | 7.45 | 6.98 | 52.3 |