| 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: | Oct. 11 - Oct. 20 | |
| Average Last Frost Date: | May 11 - May 20 | |
| Koppen-Geiger Climate Zone: | Csb - Warm-Summer Mediterranean Climate | |
| Ecoregion: | 4a - Western Cascades Lowlands and Valleys | |
| Current Drought Status: | Exceptional Drought | |
| Heat Zone Days: | Rare Over 86°F |
Annual Climate Data for ZIP Code 98027 - Issaquah, WA | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Annual |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg Min Temp (°F) | 32 | 34 | 35 | 38 | 43 | 48 | 51 | 52 | 47 | 41 | 36 | 33 | 41 |
| Avg Max Temp (°F) | 43 | 47 | 51 | 57 | 63 | 68 | 74 | 75 | 69 | 59 | 48 | 43 | 58 |
| Avg Precip (In.) | 11.34 | 9.55 | 8.66 | 7.24 | 5.93 | 5.07 | 2.7 | 2.5 | 4.51 | 7.27 | 12.72 | 12.02 | 89.51 |