Last updated: June 24, 2025
In August, the average temperature in Issaquah, United States is a pleasant 18°C (65°F). Visitors can expect a comfortable range, with minimum temperatures dipping to 7°C (44°F) and highs reaching up to 35°C (94°F). Rainfall is moderate, with an average precipitation of 23 mm (0.9 in) spread over about 5 days, and relative humidity hovering around 63%. Whether you're exploring the outdoors or enjoying local culture, the weather provides a delightful backdrop for your adventures!
In August in Issaquah, the average temperature is 18°C (65°F), with maximums reaching up to 35°C (94°F) and minimums dropping as low as 7°C (44°F). This diverse range of temperatures makes Issaquah an ideal destination for travelers seeking a mix of warmth and coolness.
In Issaquah in August, the precipitation amount is 23 mm (0.9 in) over the course of 5 days.
In Issaquah in August, humidity is 63%. With an average temperature of 18°C (65°F), this humidity feels like a comfortable embrace, making for an enjoyable travel experience that allows for leisurely exploration without feeling overly sticky or oppressive.
In Issaquah in August, the maximum UV index is 8, which corresponds to a very high Exposure Category. This means that the time to burn is only 15 minutes. For more detailed information, you can refer to the Hourly UV Index in Issaquah.
UV Risk Categories
Weather in Issaquah varies notably across the year, with each month offering distinct climate conditions. This page compares August’s weather to other months in Issaquah, focusing on differences in temperature, rainfall, humidity, and UV levels.
| Temperature | Precipitation | Humidity | UV | |
|---|---|---|---|---|
| January Weather | 5°C (40°F) | 199 mm (7.9 inches) | 86% | low |
| February Weather | 4°C (39°F) | 234 mm (9.2 inches) | 86% | moderate |
| March Weather | 7°C (44°F) | 152 mm (6.0 inches) | 87% | moderate |
| April Weather | 9°C (49°F) | 144 mm (5.7 inches) | 84% | high |
| May Weather | 13°C (55°F) | 85 mm (3.3 inches) | 81% | very high |
| June Weather | 16°C (60°F) | 78 mm (3.1 inches) | 82% | very high |
| July Weather | 18°C (65°F) | 28 mm (1.1 inches) | 79% | very high |
| August Weather | 18°C (65°F) | 23 mm (0.9 inches) | 63% | very high |
| September Weather | 15°C (60°F) | 115 mm (4.5 inches) | 62% | high |
| October Weather | 10°C (50°F) | 204 mm (8.1 inches) | 83% | moderate |
| November Weather | 7°C (45°F) | 217 mm (8.5 inches) | 89% | low |
| December Weather | 4°C (40°F) | 235 mm (9.3 inches) | 88% | low |