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Rock Island, WA
Full City Profile · Washington · Kittitas County County
2.7
/5.0
C+
Fair
1,142
Population
1,011/sq mi density
$55,114
Median Income
$22,901 per capita
$255,500
Home Value
$429,229 Zillow
$1,094
Median Rent
19.9% income on rent
51°F
Avg Temperature
279 sunny days/yr
111
Violent Crime/100K
2,755 property/100K
C+
Overall
2.7 / 5.0
Fair overall score based on economy, affordability, safety and education
A
Economy
4.0 / 5.0
$55,114 median income, 1.0% unemployment
A
Affordability
4.1 / 5.0
$255,500 home value, $1,094/mo rent
F
Safety
1.0 / 5.0
111 violent crimes/100K
D
Education
1.8 / 5.0
10.3% bachelor's degree or higher
Rock Island experiences four distinct seasons with an average annual temperature of 51°F (11°C). Winters average 29°F in January while summers reach 75°F in July. The area gets 279 sunny days per year. Annual precipitation totals 7.8 inches. Air quality is rated Good with a median AQI of 28.
Temperature
29°F Jan (-2°C)
75°F Jul (24°C)
| Annual Average | 51.2°F |
| 5% below US avg | |
| January Average | 29°F (-2°C) |
| July Average | 75°F (24°C) |
| Sunny Days | 279 days/yr |
Geography
| Elevation | 651 ft (198 m) |
| Area | 0.5 sq mi (1.4 km²) |
| Population Density | 1,011/sq mi |
| Coordinates | 47.3732°N, 120.1421°W |
| Timezone | America/Los_Angeles |
| County | Kittitas County County |
| Nearest Airport | Grant County International (MWH) 40 miles away |
Precipitation & Snow
Air Quality
| AQI Median | 28.0 |
| Rating | Good |
Air Pollutants (EPA 2023)
| PM2.5 (Fine Particles) | 6.5 μg/m³ |
Natural Hazard Risk
| Overall Risk | Relatively Moderate |
| Risk Score | 89.1 / 100 |
| Social Vulnerability | 40.2 / 100 |
| Community Resilience | 64.6 / 100 |
Hazard Breakdown
| Tornado | Very Low |
| Earthquake | Relatively Moderate |
| Wildfire | Relatively High |
| Flood | Relatively Moderate |
| Hail | Very Low |
| Strong Wind | Very Low |
| Heat Wave | Relatively Low |
| Winter Weather | Relatively Low |
| Lightning | Relatively Low |
| Ice Storm | Very Low |
| Drought | Very Low |
| Cold Wave | Relatively Low |
| Landslide | Relatively High |
| Volcano | Very Low |
| Avalanche | Very High |
Source: FEMA National Risk Index v1.20 (Dec 2025)
Tsunami History
1 tsunami recorded within 500 km. Highest wave on record: 19.8 m (65 ft).
| Year | Location | Cause | Max Wave | Deaths | Distance |
| 1949 | COLUMBIA RIVER VALLEY, WA | Meteorological | 19.8 m | — | 143 km |
Source: NOAA/NCEI Historical Tsunami Database. Sorted by wave height.
Nearby Volcanoes
4 volcanoes within 200 km. Closest: Glacier Peak (110 km).
| Name | Type | Elevation | Last Eruption | Distance |
| Glacier Peak | Stratovolcano | 3,213 m (10,541 ft) | 1700 | 110 km |
| Rainier | Stratovolcano | 4,392 m (14,409 ft) | 1450 | 135 km |
| Adams | Stratovolcano | 3,742 m (12,277 ft) | 950 | 165 km |
| Baker | Stratovolcano(es) | 3,285 m (10,778 ft) | 1880 | 199 km |
Source: Smithsonian Institution Global Volcanism Program (GVP). Sorted by distance.
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 29°F (-2°C) | 1.5 in | |
| February | 32°F (0°C) | 1.1 in | |
| March | 40°F (5°C) | 0.8 in | |
| April | 48°F (9°C) | 0.6 in | |
| May | 56°F (13°C) | 0.7 in | |
| June | 64°F (18°C) | 0.6 in | |
| July | 75°F (24°C) | 0.3 in | Warmest, Driest |
| August | 70°F (21°C) | 0.5 in | |
| September | 60°F (16°C) | 0.5 in | |
| October | 48°F (9°C) | 0.6 in | |
| November | 35°F (2°C) | 1.5 in | |
| December | 26°F (-3°C) | 1.9 in | Coldest, Wettest |
Rock Island has a seasonal temperature swing of 48°F / from 26°F in December to 75°F in July. Total annual precipitation is 10.6 inches, with December being the wettest month (1.9") and July the driest (0.3").