July weather in Mercer Island, WA
The average temperature in Mercer Island in July is 67.4°F (57.5°F–77.3°F). Average precipitation: 0.56 inches.
July is a summer month in Mercer Island, and is warmer than the annual average of 53.8°F. Daily temperatures swing about 19.8°F between overnight low and afternoon high. Expect about 3 days with precipitation. Daylight averages about 15h 24m. For travel, July is one of the best months of the year to visit.
Avg High
77.3°F
Avg Low
57.5°F
Precipitation
0.56 in
Daylight
15h 24m
July records in Mercer Island
| Date | Record High | Record Low | Record Precip |
|---|---|---|---|
| July 1 | 91.0°F (2014) | 48.0°F (1948) | 0.74 in (1954) |
| July 2 | 91.9°F (2015) | 46.9°F (1955) | 0.28 in (2019) |
| July 3 | 93.0°F (2015) | 45.0°F (1949) | 0.23 in (2008) |
| July 4 | 91.9°F (2015) | 45.0°F (1949) | 0.25 in (1948) |
| July 5 | 91.0°F (1958) | 51.1°F (2012) | 0.72 in (1961) |
| July 6 | 93.9°F (1960) | 46.9°F (1952) | 0.46 in (1948) |
| July 7 | 93.0°F (2024) | 48.9°F (1949) | 0.59 in (2002) |
| July 8 | 93.9°F (2010) | 48.9°F (1948) | 0.52 in (1953) |
| July 9 | 97.0°F (2024) | 51.1°F (1948) | 0.22 in (1954) |
| July 10 | 90.0°F (2003) | 50.0°F (1960) | 0.20 in (2004) |
| July 11 | 95.0°F (2007) | 51.1°F (1960) | 0.00 in (1948) |
| July 12 | 97.0°F (1961) | 50.0°F (1954) | 0.09 in (2011) |
| July 13 | 96.1°F (1961) | 51.1°F (1948) | 0.06 in (1953) |
| July 14 | 90.0°F (1952) | 52.0°F (1948) | 0.35 in (1957) |
| July 15 | 91.9°F (1958) | 53.1°F (1948) | 0.11 in (1964) |
| July 16 | 93.9°F (2025) | 52.0°F (1950) | 0.66 in (1999) |
| July 17 | 91.0°F (2009) | 51.1°F (1952) | 0.08 in (1999) |
| July 18 | 91.9°F (2015) | 52.0°F (1952) | 0.31 in (2007) |
| July 19 | 98.1°F (2015) | 52.0°F (1955) | 0.50 in (1950) |
| July 20 | 90.0°F (1956) | 51.1°F (1955) | 0.72 in (2012) |
| July 21 | 95.0°F (2006) | 51.1°F (1949) | 0.24 in (2007) |
| July 22 | 91.9°F (1959) | 52.0°F (2011) | 0.43 in (1963) |
| July 23 | 95.0°F (2004) | 48.9°F (1963) | 0.49 in (1949) |
| July 24 | 95.0°F (2004) | 48.9°F (1953) | 0.10 in (2023) |
| July 25 | 89.1°F (2018) | 50.0°F (1948) | 0.33 in (2011) |
| July 26 | 93.9°F (2022) | 52.0°F (1952) | 0.52 in (1955) |
| July 27 | 96.1°F (1958) | 48.9°F (1956) | 0.13 in (1950) |
| July 28 | 98.1°F (1958) | 48.9°F (1959) | 0.12 in (1950) |
| July 29 | 105.1°F (2009) | 48.0°F (1954) | 0.05 in (2024) |
| July 30 | 96.1°F (2009) | 52.0°F (1954) | 0.23 in (1955) |
| July 31 | 96.1°F (1965) | 48.9°F (2008) | 0.20 in (2008) |