| 2023 Hardiness Zone: | Zone 6a: -10°F to -5°F Zone 6b: -5°F to 0°F Zone 5b: -15°F to -10°F |
| 2012 Hardiness Zone: | Zone 6a: -10°F to -5°F Zone 6b: -5°F to 0°F Zone 5a: -20°F to -15°F Zone 5b: -15°F to -10°F |
| 1990 Hardiness Zone: | Zone 5a: -20F to -15F |
| Average First Frost Date: | Sep.11 - Sep. 20 |
| Average Last Frost Date: | May 21 - May 31 |
| Koppen-Geiger Climate Zone: | Dsb - Humid Continental Climate - Dry Cool Summer |
| Ecoregion: | 15r - Okanogan-Colville Xeric Valleys and Foothills |
| Heat Zone Days: | 31 - 45 days Over 86°F |
Annual Climate Data for ZIP Code 99109 - Chewelah, WA | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 19 | 22 | 28 | 33 | 40 | 46 | 50 | 48 | 41 | 32 | 27 | 20 | 34 |
| Avg Max Temp (°F) | 33 | 39 | 50 | 60 | 68 | 76 | 83 | 84 | 75 | 59 | 41 | 33 | 58 |
| Avg Precip (In.) | 2.26 | 1.94 | 1.99 | 1.6 | 2.12 | 1.72 | 1.19 | 1 | 1.03 | 1.23 | 2.68 | 2.9 | 21.65 |