Mercer Island weather in August
In August, Mercer Island sees average daytime highs of 75°F and overnight lows near 58°F, with 1.3 in of rain across 4.8 wet days and about 14.1 hours of daylight. It is the 1st-warmest and 11th-wettest month of the year here.
Highs ease over the month, from about 76°F in the first days to 73°F by the end. The sky is clear or mostly clear about 47% of the time in August, and the air most often feels comfortable.
Daylight stretches from about 14 h 48 min at the start of August to 13 h 18 min by month's end. Set against the rest of the year, August is Mercer Island's 1st-clearest and 11th-windiest month. For the whole year in context, see Mercer Island's year-round climate.
- Daytime high
- 75°
- 1st warmest
- Overnight low
- 58°
- 12th coldest
- Rainfall
- 1.3 in
- 4.8 wet days
- Daylight
- 14 h 06 min
- 5:10 AM – 7:16 PM
- Cloud cover
- 44%
- 1st clearest
- Wind
- 4 mph
- 11th windiest
- Solar energy
- 5.4 kWh/m²
- Travel score
- 8.0
- out of 10
Mercer Island is city in King County, Washington State, USA.
- Density
- 738/km²
- people per km²
- Founded
- 1960
Air quality: WHO Ambient Air Quality Database. Density & description: Wikidata (CC0), GeoNames.
Temperature in August
Highs ease over the month, from about 76°F in the first days to 73°F by the end.
A typical August day in Mercer Island reaches about 75°F in the afternoon and slips back to 58°F overnight — a 17°F spread between the day's warmth and the night's chill. On most days the high lands between 67°F and 83°F. Set against its neighbours, August runs on par with July and about 6°F warmer than September.
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Avg high (°F) | 76 | 76 | 76 | 76 | 76 | 76 | 76 | 76 | 76 | 76 | 76 | 76 | 76 | 75 | 75 | 75 | 75 | 75 | 75 | 74 | 74 | 74 | 74 | 74 | 74 | 74 | 73 | 73 | 73 | 73 | 73 |
| Avg low (°F) | 58 | 58 | 58 | 58 | 58 | 58 | 58 | 58 | 58 | 58 | 58 | 58 | 58 | 58 | 58 | 58 | 58 | 58 | 58 | 58 | 57 | 57 | 57 | 57 | 57 | 57 | 57 | 56 | 56 | 56 | 56 |
| Avg high (°F) | Avg low (°F) | |
|---|---|---|
| 1 | 76 | 58 |
| 2 | 76 | 58 |
| 3 | 76 | 58 |
| 4 | 76 | 58 |
| 5 | 76 | 58 |
| 6 | 76 | 58 |
| 7 | 76 | 58 |
| 8 | 76 | 58 |
| 9 | 76 | 58 |
| 10 | 76 | 58 |
| 11 | 76 | 58 |
| 12 | 76 | 58 |
| 13 | 76 | 58 |
| 14 | 75 | 58 |
| 15 | 75 | 58 |
| 16 | 75 | 58 |
| 17 | 75 | 58 |
| 18 | 75 | 58 |
| 19 | 75 | 58 |
| 20 | 74 | 58 |
| 21 | 74 | 57 |
| 22 | 74 | 57 |
| 23 | 74 | 57 |
| 24 | 74 | 57 |
| 25 | 74 | 57 |
| 26 | 74 | 57 |
| 27 | 73 | 57 |
| 28 | 73 | 56 |
| 29 | 73 | 56 |
| 30 | 73 | 56 |
| 31 | 73 | 56 |
Mercer Island weather by month
How August compares with the rest of the year at a glance. August is the 1st-warmest and 11th-wettest month here — the current month is highlighted below.
| Month | High / Low (°F) | Rainfall (inches) | Wet days | Snow days | Daylight (hours) | Travel score |
|---|---|---|---|---|---|---|
| Jan | 46° / 38° | 6.9 | 18.4 | 2.2 | 8.7 | 1.0 |
| Feb | 49° / 39° | 4.7 | 14.5 | 1.8 | 9.9 | 1.6 |
| Mar | 52° / 40° | 5.5 | 17.5 | 0.8 | 11.6 | 2.3 |
| Apr | 57° / 44° | 4.5 | 14.9 | 0.1 | 13.3 | 3.5 |
| May | 64° / 49° | 3.0 | 12 | 0 | 14.9 | 5.3 |
| Jun | 68° / 53° | 2.3 | 9.5 | 0 | 15.7 | 6.3 |
| Jul | 74° / 57° | 1.0 | 5 | 0 | 15.4 | 7.9 |
| Aug | 75° / 58° | 1.3 | 4.8 | 0 | 14.1 | 8.0 |
| Sep | 69° / 53° | 2.6 | 8.4 | 0 | 12.4 | 6.8 |
| Oct | 59° / 47° | 5.3 | 14.1 | 0 | 10.6 | 4.2 |
| Nov | 50° / 42° | 7.6 | 18 | 0.6 | 9.1 | 1.9 |
| Dec | 45° / 38° | 7.0 | 17.6 | 2.1 | 8.3 | 0.8 |
Cloud cover in August
The sky is clear or mostly clear about 47% of the time in August, the clearest month of the year.
Beyond those clear spells, partly cloudy skies cover about 17% of August, with mostly cloudy or overcast conditions the remaining 36%. Skies tend to cloud over as the month goes on.
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Clearer (%) | 71 | 69 | 69 | 69 | 68 | 68 | 66 | 66 | 66 | 65 | 64 | 64 | 64 | 63 | 63 | 63 | 63 | 63 | 63 | 63 | 62 | 62 | 62 | 62 | 62 | 61 | 61 | 60 | 60 | 61 | 60 |
| Cloudier (%) | 29 | 31 | 31 | 31 | 32 | 32 | 34 | 34 | 34 | 35 | 36 | 36 | 36 | 37 | 37 | 37 | 37 | 37 | 37 | 37 | 38 | 38 | 38 | 38 | 38 | 39 | 39 | 40 | 40 | 39 | 40 |
| Clearer (%) | Cloudier (%) | |
|---|---|---|
| 1 | 71 | 29 |
| 2 | 69 | 31 |
| 3 | 69 | 31 |
| 4 | 69 | 31 |
| 5 | 68 | 32 |
| 6 | 68 | 32 |
| 7 | 66 | 34 |
| 8 | 66 | 34 |
| 9 | 66 | 34 |
| 10 | 65 | 35 |
| 11 | 64 | 36 |
| 12 | 64 | 36 |
| 13 | 64 | 36 |
| 14 | 63 | 37 |
| 15 | 63 | 37 |
| 16 | 63 | 37 |
| 17 | 63 | 37 |
| 18 | 63 | 37 |
| 19 | 63 | 37 |
| 20 | 63 | 37 |
| 21 | 62 | 38 |
| 22 | 62 | 38 |
| 23 | 62 | 38 |
| 24 | 62 | 38 |
| 25 | 62 | 38 |
| 26 | 61 | 39 |
| 27 | 61 | 39 |
| 28 | 60 | 40 |
| 29 | 60 | 40 |
| 30 | 61 | 39 |
| 31 | 60 | 40 |
Chance of precipitation in August
Mercer Island gets around 1.3 in of rain over 4.8 wet days in August. The line is the day-by-day chance of measurable precipitation.
Day to day, the chance of measurable rain averages around 15% and peaks near 23% on the wettest days. The odds climb toward the end of the month.
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Rain chance (%) | 10 | 10 | 11 | 11 | 11 | 11 | 12 | 12 | 13 | 13 | 13 | 14 | 14 | 14 | 14 | 15 | 15 | 15 | 16 | 16 | 17 | 17 | 18 | 18 | 19 | 20 | 20 | 21 | 21 | 22 | 23 |
| Rain chance (%) | |
|---|---|
| 1 | 10 |
| 2 | 10 |
| 3 | 11 |
| 4 | 11 |
| 5 | 11 |
| 6 | 11 |
| 7 | 12 |
| 8 | 12 |
| 9 | 13 |
| 10 | 13 |
| 11 | 13 |
| 12 | 14 |
| 13 | 14 |
| 14 | 14 |
| 15 | 14 |
| 16 | 15 |
| 17 | 15 |
| 18 | 15 |
| 19 | 16 |
| 20 | 16 |
| 21 | 17 |
| 22 | 17 |
| 23 | 18 |
| 24 | 18 |
| 25 | 19 |
| 26 | 20 |
| 27 | 20 |
| 28 | 21 |
| 29 | 21 |
| 30 | 22 |
| 31 | 23 |
Humidity in August
Most of August feels comfortable — the stacked bands show each day's mix of comfort levels, read off the dew point.
By dew point, August lands in the comfortable band about 49% of days. It rarely turns muggy — the humid and sticky bands barely register.
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Dry (%) | 39 | 38 | 38 | 38 | 37 | 37 | 37 | 36 | 36 | 36 | 36 | 36 | 36 | 37 | 38 | 39 | 41 | 42 | 44 | 45 | 47 | 48 | 49 | 50 | 52 | 53 | 54 | 55 | 57 | 57 | 58 |
| Comfortable (%) | 53 | 54 | 54 | 54 | 55 | 55 | 55 | 55 | 55 | 55 | 55 | 55 | 55 | 54 | 53 | 52 | 50 | 49 | 48 | 47 | 46 | 45 | 45 | 44 | 43 | 42 | 42 | 41 | 40 | 40 | 39 |
| Humid (%) | 8 | 8 | 8 | 8 | 8 | 8 | 8 | 9 | 9 | 9 | 9 | 9 | 9 | 9 | 9 | 9 | 9 | 8 | 8 | 8 | 7 | 7 | 6 | 6 | 5 | 5 | 4 | 4 | 3 | 3 | 3 |
| Dry (%) | Comfortable (%) | Humid (%) | |
|---|---|---|---|
| 1 | 39 | 53 | 8 |
| 2 | 38 | 54 | 8 |
| 3 | 38 | 54 | 8 |
| 4 | 38 | 54 | 8 |
| 5 | 37 | 55 | 8 |
| 6 | 37 | 55 | 8 |
| 7 | 37 | 55 | 8 |
| 8 | 36 | 55 | 9 |
| 9 | 36 | 55 | 9 |
| 10 | 36 | 55 | 9 |
| 11 | 36 | 55 | 9 |
| 12 | 36 | 55 | 9 |
| 13 | 36 | 55 | 9 |
| 14 | 37 | 54 | 9 |
| 15 | 38 | 53 | 9 |
| 16 | 39 | 52 | 9 |
| 17 | 41 | 50 | 9 |
| 18 | 42 | 49 | 8 |
| 19 | 44 | 48 | 8 |
| 20 | 45 | 47 | 8 |
| 21 | 47 | 46 | 7 |
| 22 | 48 | 45 | 7 |
| 23 | 49 | 45 | 6 |
| 24 | 50 | 44 | 6 |
| 25 | 52 | 43 | 5 |
| 26 | 53 | 42 | 5 |
| 27 | 54 | 42 | 4 |
| 28 | 55 | 41 | 4 |
| 29 | 57 | 40 | 3 |
| 30 | 57 | 40 | 3 |
| 31 | 58 | 39 | 3 |
Wind in August
Winds average 4 mph in August.
Across August, daily wind ranges from about 4 mph on the calmest days to 4 mph at its breeziest. It stays fairly steady from day to day.
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Wind speed (mph) | 4 | 4 | 4 | 4 | 4 | 4 | 4 | 4 | 4 | 4 | 4 | 4 | 4 | 4 | 4 | 4 | 4 | 4 | 4 | 4 | 4 | 4 | 4 | 4 | 4 | 4 | 4 | 4 | 4 | 4 | 4 |
| Feels | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm | calm |
| Wind speed (mph) | Feels | |
|---|---|---|
| 1 | 4 | calm |
| 2 | 4 | calm |
| 3 | 4 | calm |
| 4 | 4 | calm |
| 5 | 4 | calm |
| 6 | 4 | calm |
| 7 | 4 | calm |
| 8 | 4 | calm |
| 9 | 4 | calm |
| 10 | 4 | calm |
| 11 | 4 | calm |
| 12 | 4 | calm |
| 13 | 4 | calm |
| 14 | 4 | calm |
| 15 | 4 | calm |
| 16 | 4 | calm |
| 17 | 4 | calm |
| 18 | 4 | calm |
| 19 | 4 | calm |
| 20 | 4 | calm |
| 21 | 4 | calm |
| 22 | 4 | calm |
| 23 | 4 | calm |
| 24 | 4 | calm |
| 25 | 4 | calm |
| 26 | 4 | calm |
| 27 | 4 | calm |
| 28 | 4 | calm |
| 29 | 4 | calm |
| 30 | 4 | calm |
| 31 | 4 | calm |
Sunrise & sunset in August
Daylight runs from about 14 h 48 min at the start of August to 13 h 18 min by month's end. The lit band spans sunrise to sunset each day.
Days shrink by about 90 minutes over August. Sunrise moves from 4:50 AM to 5:31 AM, and sunset from 7:39 PM to 6:47 PM.
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Daylight (h) | 14.8 | 14.8 | 14.7 | 14.7 | 14.6 | 14.6 | 14.5 | 14.5 | 14.4 | 14.4 | 14.3 | 14.3 | 14.2 | 14.2 | 14.1 | 14.1 | 14.0 | 14.0 | 13.9 | 13.9 | 13.8 | 13.8 | 13.7 | 13.7 | 13.6 | 13.5 | 13.5 | 13.4 | 13.4 | 13.3 | 13.3 |
| Sunrise (AM) | 4:50 | 4:52 | 4:53 | 4:54 | 4:56 | 4:57 | 4:58 | 5:00 | 5:01 | 5:02 | 5:04 | 5:05 | 5:06 | 5:08 | 5:09 | 5:10 | 5:12 | 5:13 | 5:14 | 5:16 | 5:17 | 5:19 | 5:20 | 5:21 | 5:23 | 5:24 | 5:25 | 5:27 | 5:28 | 5:30 | 5:31 |
| Sunset (PM) | 7:39 | 7:38 | 7:37 | 7:35 | 7:34 | 7:32 | 7:31 | 7:29 | 7:27 | 7:26 | 7:24 | 7:23 | 7:21 | 7:19 | 7:17 | 7:16 | 7:14 | 7:12 | 7:10 | 7:08 | 7:06 | 7:05 | 7:03 | 7:01 | 6:59 | 6:57 | 6:55 | 6:53 | 6:51 | 6:49 | 6:47 |
| Daylight (h) | Sunrise (AM) | Sunset (PM) | |
|---|---|---|---|
| 1 | 14.8 | 4:50 | 7:39 |
| 2 | 14.8 | 4:52 | 7:38 |
| 3 | 14.7 | 4:53 | 7:37 |
| 4 | 14.7 | 4:54 | 7:35 |
| 5 | 14.6 | 4:56 | 7:34 |
| 6 | 14.6 | 4:57 | 7:32 |
| 7 | 14.5 | 4:58 | 7:31 |
| 8 | 14.5 | 5:00 | 7:29 |
| 9 | 14.4 | 5:01 | 7:27 |
| 10 | 14.4 | 5:02 | 7:26 |
| 11 | 14.3 | 5:04 | 7:24 |
| 12 | 14.3 | 5:05 | 7:23 |
| 13 | 14.2 | 5:06 | 7:21 |
| 14 | 14.2 | 5:08 | 7:19 |
| 15 | 14.1 | 5:09 | 7:17 |
| 16 | 14.1 | 5:10 | 7:16 |
| 17 | 14.0 | 5:12 | 7:14 |
| 18 | 14.0 | 5:13 | 7:12 |
| 19 | 13.9 | 5:14 | 7:10 |
| 20 | 13.9 | 5:16 | 7:08 |
| 21 | 13.8 | 5:17 | 7:06 |
| 22 | 13.8 | 5:19 | 7:05 |
| 23 | 13.7 | 5:20 | 7:03 |
| 24 | 13.7 | 5:21 | 7:01 |
| 25 | 13.6 | 5:23 | 6:59 |
| 26 | 13.5 | 5:24 | 6:57 |
| 27 | 13.5 | 5:25 | 6:55 |
| 28 | 13.4 | 5:27 | 6:53 |
| 29 | 13.4 | 5:28 | 6:51 |
| 30 | 13.3 | 5:30 | 6:49 |
| 31 | 13.3 | 5:31 | 6:47 |
Solar energy in August
Average shortwave solar energy reaching the ground each day in August, about 5.4 kWh/m².
For context, solar energy here swings from a low near 0.88 kWh/m² to a high of 6.14 kWh/m² in July across the year — August's 5.4 kWh/m² sits near the top of that range.
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 | 31 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Solar energy (kWh/m²) | 6.1 | 6.0 | 6.0 | 6.0 | 5.9 | 5.9 | 5.8 | 5.8 | 5.7 | 5.7 | 5.7 | 5.6 | 5.6 | 5.5 | 5.5 | 5.4 | 5.4 | 5.3 | 5.3 | 5.3 | 5.2 | 5.2 | 5.1 | 5.0 | 5.0 | 5.0 | 4.9 | 4.9 | 4.8 | 4.8 | 4.7 |
| Level | Intense | Intense | Intense | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright | Bright |
| Solar energy (kWh/m²) | Level | |
|---|---|---|
| 1 | 6.1 | Intense |
| 2 | 6.0 | Intense |
| 3 | 6.0 | Intense |
| 4 | 6.0 | Bright |
| 5 | 5.9 | Bright |
| 6 | 5.9 | Bright |
| 7 | 5.8 | Bright |
| 8 | 5.8 | Bright |
| 9 | 5.7 | Bright |
| 10 | 5.7 | Bright |
| 11 | 5.7 | Bright |
| 12 | 5.6 | Bright |
| 13 | 5.6 | Bright |
| 14 | 5.5 | Bright |
| 15 | 5.5 | Bright |
| 16 | 5.4 | Bright |
| 17 | 5.4 | Bright |
| 18 | 5.3 | Bright |
| 19 | 5.3 | Bright |
| 20 | 5.3 | Bright |
| 21 | 5.2 | Bright |
| 22 | 5.2 | Bright |
| 23 | 5.1 | Bright |
| 24 | 5.0 | Bright |
| 25 | 5.0 | Bright |
| 26 | 5.0 | Bright |
| 27 | 4.9 | Bright |
| 28 | 4.9 | Bright |
| 29 | 4.8 | Bright |
| 30 | 4.8 | Bright |
| 31 | 4.7 | Bright |
Hazard calendar for Mercer Island
None of Mercer Island's seasonal hazards are active in August. The full-year calendar below shows when the rainy season, cyclone risk and dust haze do peak.
Mercer Island's rainy season runs October–April, when most of the year's rain falls.
Is August a good time to visit Mercer Island?
Our two travel scores rate August for general sightseeing and for beach or pool weather — 0 (poor) to 10 (ideal).
August is one of the better times to visit Mercer Island for general sightseeing. The water and warmth also suit a beach or pool day.
What to pack for Mercer Island in August
From August's temperature range, rain chance, sun and wind — what's worth putting in the bag.
In August, Mercer Island sees daytime highs around 75°F and nights near 58°F. Worth packing: light clothes and sun protection. About 5 days see rain.
UV index in Mercer Island in August
Clear-sky midday UV in August peaks around 6 — enough to warrant sun protection. The full-year curve, shaded by WHO exposure level, is below.
Under clear skies, the midday UV index in Mercer Island peaks around July 17 at about 8 (very high) — sunscreen and a hat are worth it in the middle of the day. It bottoms out near December 18 at about 1 (low).
The index reaches 3 or more — the level where the WHO recommends sun protection — in 7 months of the year.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| UV index (midday) | 1 | 1 | 4 | 5 | 7 | 6 | 8 | 6 | 4 | 3 | 1 | 1 |
| Level | Low | Low | Moderate | Moderate | High | High | Very high | High | Moderate | Moderate | Low | Low |
| UV index (midday) | Level | |
|---|---|---|
| Jan | 1 | Low |
| Feb | 1 | Low |
| Mar | 4 | Moderate |
| Apr | 5 | Moderate |
| May | 7 | High |
| Jun | 6 | High |
| Jul | 8 | Very high |
| Aug | 6 | High |
| Sep | 4 | Moderate |
| Oct | 3 | Moderate |
| Nov | 1 | Low |
| Dec | 1 | Low |
Air quality in Mercer Island in August
Average fine-particle pollution (PM2.5) through the year — so you can see where August falls, not just the annual average.
Air quality in Mercer Island is worst in September — around 22 µg/m³ PM2.5 (moderate), about 3.4× the cleanest month (December, 7 µg/m³).
Modeled monthly averages (CAMS reanalysis, 2015–2024).
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| PM2.5 (µg/m³) | 8 | 9 | 12 | 12 | 11 | 10 | 10 | 18 | 22 | 12 | 8 | 7 |
| Level | Good | Good | Moderate | Good | Good | Good | Good | Moderate | Moderate | Good | Good | Good |
| PM2.5 (µg/m³) | Level | |
|---|---|---|
| Jan | 8 | Good |
| Feb | 9 | Good |
| Mar | 12 | Moderate |
| Apr | 12 | Good |
| May | 11 | Good |
| Jun | 10 | Good |
| Jul | 10 | Good |
| Aug | 18 | Moderate |
| Sep | 22 | Moderate |
| Oct | 12 | Good |
| Nov | 8 | Good |
| Dec | 7 | Good |
Where is Mercer Island?
Mercer Island sits at 47.6°N, 122.2°W, 335 ft above sea level, in United States. The nearest listed city is Columbia City, 2.5 mi away.
Topography around Mercer Island
How much the land rises and falls, and what covers it, within 2, 10 and 50 miles of Mercer Island.
Within 2 miles, the terrain around Mercer Island has only modest variations in elevation — a maximum elevation change of 400 ft around an average of 105 ft above sea level; within 10 miles, large variations in elevation — a maximum elevation change of 2,037 ft; within 50 miles, extreme variations in elevation — a maximum elevation change of 8,179 ft.
The land around Mercer Island is covered by trees (46%) and water (43%) within 2 miles, trees (48%), artificial surfaces (27%) and water (20%) within 10 miles, and trees (75%) within 50 miles.
United States travel facts
- Power plugs
- Type A / B
- 120 V · 60 Hz
- Prices
- ≈ 100% of US
- price level, 2025
- GDP per capita
- $90,027
- 2025
- Happiness
- 6.8 / 10
- World Happiness, 2025
- Safe drinking water
- 98%
- of population, 2024
- Homicide rate
- 5.8
- per 100k, 2023
- Road deaths
- 12.7
- per 100k/yr, 2019
- Income group
- High
- World Bank
- Religion
Sources: World Bank, US State Department, World Happiness Report, WHO/UNICEF, EF EPI, CIA World Factbook.
Data sources
Temperature, precipitation, cloud, humidity, wind and solar figures are a 1991–2020 climatology for Mercer Island (47.5707°, -122.2221°, elevation 335 ft), computed from hourly ERA5 reanalysis — contains modified Copernicus Climate Change Service information. Sun figures are astronomical calculations, not observations. City data © GeoNames, CC BY 4.0. Map outlines from Natural Earth (public domain); interactive map © Google. UV index is derived from CAMS (Copernicus Atmosphere Monitoring Service) clear-sky UV data — contains modified Copernicus Atmosphere Monitoring Service information. Monthly air-quality (PM2.5) seasonality is from the CAMS EAC4 reanalysis (Copernicus Atmosphere Monitoring Service), scaled to the WHO annual mean where available. Topography is sampled from the Copernicus DEM GLO-90 elevation model (© ESA/Airbus) and ESA WorldCover 2021 land cover (CC BY 4.0).