Issaquah
Issaquah / East King · Zone 8b · Issaquah plateau, Cascade foothills. Author's office location. Higher elevation than Kent valley floor; slightly cooler, more continental influence.
Data through May 21, 2026
Season Progress
Cumulative GDD₃₂ year to date. Other stations shown faded for regional context.
Season vs. History
As of May 21, 2026, Issaquah has accumulated 2307.4 GDD₃₂, which is 23% ahead of the 2020–2025 average of 1874.6 for this date. This season is tracking closest to 2024.
Cumulative GDD₃₂ by day of year. Current season (bold) against 2020–2025 individual years (faded) and their average (dashed).
Soil Temperature
Daily soil temperature at 2-inch depth. Bands: below 40°F (too cold), 40-50°F (cool-season), above 50°F (warm-season activation).
Frost Events
Every night the temperature dropped below 32°F. Color indicates severity: light (28-32°F), moderate (24-28°F), hard (<24°F).
Precipitation
Daily rainfall (bars) and cumulative total (bold line) for Issaquah. Other stations shown faded.
Chill Hours
Cumulative hours below 45°F since January 1. Dashed lines show common fruit tree thresholds.
Dew Point & Disease Risk
Daily average dew point. Watch zone: 50-55°F. Active disease risk above 55°F.
Water Balance
Cumulative precipitation (solid) vs. evapotranspiration (dashed) for Issaquah. When ET crosses above precipitation, start irrigating.
Sunshine Hours
7-day rolling average of daily sunshine. Other stations faded for comparison.
Monthly Summary
| Month | Low | High | Precip | Frost | Spray | GDD₃₂ | Sun hrs |
|---|---|---|---|---|---|---|---|
| Jan | 22° | 64.3° | 6.3" | 6 | 14 | 359.2 | 148.9 |
| Feb | 26.4° | 66.1° | 5.69" | 6 | 10 | 336 | 144.4 |
| Mar | 32.4° | 58° | 7.37" | 0 | 5 | 437 | 161.1 |
| Apr | 35.4° | 75° | 2.2" | 0 | 15 | 615.8 | 228.7 |
| May | 42.4° | 80.2° | 0.92" | 0 | 11 | 559.4 | 178.1 |
Other Stations
Data from the HortGuide station network via Open-Meteo. Your microclimate varies. Updated daily.