Best Time to Visit Mercer Island: Month-by-Month Guide
Best months for Mercer Island: July, August, September.
- Best months for Mercer Island: July, August, September.
- Peak season is August, July, September. Expect higher prices and more visitors (estimated from the climate, not from visitor counts).
- Shoulder season: June. Good weather without the busiest period.
- Wettest months: January, November, December.
- The least pleasant month is December (score 4.0).
Year at a glance
Weather by month
| Month | Avg high | Avg low | Rainfall | Rainy days | Humidity | Sunshine | Score |
|---|---|---|---|---|---|---|---|
| January | 8°C | 4°C | 176 mm | 18 | – | – | 4.0 |
| February | 10°C | 4°C | 122 mm | 14 | – | – | 5.0 |
| March | 12°C | 5°C | 139 mm | 17 | – | – | 4.9 |
| April | 15°C | 7°C | 114 mm | 16 | – | – | 5.6 |
| May | 18°C | 10°C | 76 mm | 13 | – | – | 6.8 |
| June | 21°C | 12°C | 60 mm | 10 | – | – | 7.6 |
| July | 25°C | 14°C | 25 mm | 5 | – | – | 8.4 |
| August | 25°C | 14°C | 32 mm | 5 | – | – | 8.4 |
| September | 22°C | 12°C | 67 mm | 8 | – | – | 7.9 |
| October | 16°C | 9°C | 134 mm | 15 | – | – | 5.9 |
| November | 11°C | 6°C | 192 mm | 18 | – | – | 4.3 |
| December | 8°C | 4°C | 178 mm | 18 | – | – | 4.0 |
Frequently asked questions
When is the best time to visit Mercer Island?
The best months are July, August, September.
When is the rainy season in Mercer Island?
The wettest months are January, November, December.