Weather & Climate in Mossyrock, WA
Temperature, precipitation, air quality, natural hazards, and monthly weather data.
Mossyrock experiences four distinct seasons with an average annual temperature of 52°F (11°C). Winters average 39°F in January while summers reach 66°F in July. Annual precipitation totals 58.7 inches (wetter than the 38-inch national average). The area receives 3.4 inches of snow annually. Air quality is rated Good with a median AQI of 22 / among the cleanest air in the country. 93% of days have good air quality. The city sits at an elevation of 658 feet.
Temperature
39°F Jan (4°C)
66°F Jul (19°C)
| Annual Average | 51.6°F |
| 4% below US avg | |
| January Average | 39°F (4°C) |
| July Average | 66°F (19°C) |
Geography
| Elevation | 658 ft (201 m) |
| Area | 0.3 sq mi (0.7 km²) |
| Population Density | 1,307/sq mi |
| Coordinates | 46.5305°N, 122.4887°W |
| Timezone | America/Los_Angeles |
| County | Lewis County County |
| Nearest Airport | Southwest Washington Regional (KLS) 35 miles away |
Precipitation & Snow
Air Quality
| AQI Median | 22.0 |
| Rating | Good |
| Good Days % | 93.3% |
| Unhealthy Days | 1 |
Natural Hazard Risk
| Overall Risk | Relatively Moderate |
| Risk Score | 89.7 / 100 |
| Social Vulnerability | 58.3 / 100 |
| Community Resilience | 45.1 / 100 |
Hazard Breakdown
| Tornado | Very Low |
| Earthquake | Relatively Moderate |
| Wildfire | Relatively Low |
| Flood | Relatively Moderate |
| Hail | Very Low |
| Strong Wind | Relatively Low |
| Heat Wave | Relatively Low |
| Winter Weather | Relatively Low |
| Lightning | Relatively Low |
| Ice Storm | Relatively Low |
| Drought | Very Low |
| Cold Wave | Very Low |
| Landslide | Relatively Moderate |
| Volcano | Relatively Moderate |
| Avalanche | Relatively High |
Source: FEMA National Risk Index v1.20 (Dec 2025)
Earthquake History
1,322 earthquakes (M2.5+) recorded within 150 km since 1990. Strongest on record: M6.8.
| Feb 28, 2001 | 7 km SSE of Longbranch, Washington | M6.8 | 71 km | 52 km |
| Jul 3, 1999 | 8 km N of Satsop, Washington | M5.8 | 96 km | 40 km |
| May 3, 1996 | 8 km NNE of Lake Marcel-Stillwater, Washington | M5.4 | 144 km | 4 km |
| Jan 29, 1995 | 3 km WSW of Des Moines, Washington | M5.0 | 96 km | 15 km |
| Jun 10, 2001 | 18 km N of Satsop, Washington | M5.0 | 105 km | 40 km |
| Jun 23, 1997 | 2 km NE of Enetai, Washington | M4.9 | 119 km | 13 km |
| Apr 25, 2003 | 26 km W of Brinnon, Washington | M4.8 | 139 km | 51 km |
| Jan 30, 2009 | 6 km ESE of Lofall, Washington | M4.7 | 140 km | 62 km |
| Jun 29, 2002 | 6 km ENE of Government Camp, Oregon | M4.5 | 147 km | 5 km |
| Jul 22, 2001 | 4 km WSW of DuPont, Washington | M4.3 | 64 km | 52 km |
| Feb 14, 2011 | 31 km S of Morton, Washington | M4.3 | 35 km | 4 km |
| Jun 17, 2010 | 30 km S of White Swan, Washington | M4.2 | 142 km | 3 km |
| May 20, 1995 | 15 km NNE of Ashford, Washington | M4.1 | 57 km | 12 km |
| Feb 23, 2017 | 11 km NE of Hoodsport, Washington | M4.1 | 113 km | 15 km |
| Aug 16, 2004 | 16 km ENE of Packwood, Washington | M4.0 | 79 km | -1 km |
| Oct 9, 1998 | 20 km S of White Swan, Washington | M4.0 | 141 km | 2 km |
| Jun 15, 1994 | 1 km WNW of Hoodsport, Washington | M4.0 | 110 km | 44 km |
| Jun 6, 2021 | 6 km NE of Government Camp, Oregon | M3.9 | 146 km | 4 km |
| Aug 8, 2023 | 9 km NNE of Snoqualmie, Washington | M3.9 | 131 km | 16 km |
| Jun 25, 2004 | 17 km W of Packwood, Washington | M3.9 | 47 km | -1 km |
Source: USGS Earthquake Catalog (M2.5+, 1990-2025). Sorted by magnitude.
Tornado History
41 tornadoes (EF0+) recorded within 100 km since 1950. Strongest on record: EF2. Total: 2 injuries.
| Date | Rating | Distance | Path | Fatalities |
| Nov 10, 1965 | EF2 | 37 km | 1.5 mi | 0 |
| Oct 18, 2019 | EF1 | 89 km | 0.7 mi | 0 |
| Dec 10, 2015 | EF1 | 85 km | 0.8 mi | 0 |
| Jan 18, 2015 | EF1 | 89 km | 4.1 mi | 0 |
| Oct 23, 2014 | EF1 | 57 km | 1.3 mi | 0 |
| Sep 30, 2013 | EF1 | 62 km | 1.0 mi | 0 |
| Sep 6, 2009 | EF1 | 78 km | 9.6 mi | 0 |
| Jan 10, 2008 | EF1 | 96 km | 10.1 mi | 0 |
| May 27, 2004 | EF1 | 47 km | 0.2 mi | 0 |
| Jun 27, 2001 | EF1 | 76 km | 2.3 mi | 0 |
| May 31, 1997 | EF1 | 78 km | 0.5 mi | 0 |
| Jun 29, 1989 | EF1 | 74 km | 1.6 mi | 0 |
| Mar 28, 1985 | EF1 | 50 km | 0.2 mi | 0 |
| Oct 13, 1984 | EF1 | 71 km | 3.0 mi | 0 |
| Aug 16, 1978 | EF1 | 89 km | 0.2 mi | 0 |
| Jun 12, 1978 | EF1 | 67 km | 1.5 mi | 0 |
| Dec 22, 1971 | EF1 | 97 km | 0.5 mi | 0 |
| Oct 28, 2024 | EF0 | 59 km | 0.2 mi | 0 |
| Oct 11, 2023 | EF0 | 74 km | 0.5 mi | 0 |
| Sep 27, 2021 | EF0 | 84 km | 3.9 mi | 0 |
Source: NOAA Storm Prediction Center (EF0+, 1950-2024, US only).
Tsunami History
4 tsunamis recorded within 500 km. Highest wave on record: 250.0 m (820 ft).
| Year | Location | Cause | Max Wave | Deaths | Distance |
| 1980 | WASHINGTON | Explosion | 250.0 m | 61 | 44 km |
| 1894 | PUYALLUP RIVER DELTA, TACOMA, WA | Meteorological | 3.0 m | 2 | 84 km |
| 1949 | PUGET SOUND, WA | Meteorological | 2.4 m | - | 86 km |
| 1949 | PUGET SOUND, WA | Eruption + Earthquake | - | 8 | 71 km |
Source: NOAA/NCEI Historical Tsunami Database.
Nearby Volcanoes
6 volcanoes within 200 km. Closest: St. Helens (44 km).
| Name | Type | Elevation | Last Eruption | Distance |
| St. Helens | Stratovolcano | 2,549 m (8,363 ft) | 2008 | 44 km |
| Rainier | Stratovolcano | 4,392 m (14,409 ft) | 1450 | 66 km |
| West Crater | Volcanic field | 1,329 m (4,360 ft) | -5750 | 79 km |
| Indian Heaven | Shield(s) | 1,806 m (5,925 ft) | -6250 | 84 km |
| Adams | Stratovolcano | 3,742 m (12,277 ft) | 950 | 85 km |
| Hood | Stratovolcano | 3,426 m (11,240 ft) | 1866 | 143 km |
Source: Smithsonian Institution Global Volcanism Program (GVP).
Wildfire History
12 wildfires (100+ acres) recorded within 100 km. Largest: COUGAR CREEK (51,866 acres, 2015).
| Year | Name | Acres Burned | Distance |
| 2015 | COUGAR CREEK | 51,866 | 94 km |
| 2017 | NORSE PEAK | 51,017 | 98 km |
| 2020 | BIG HOLLOW | 24,243 | 72 km |
| 2012 | CASCADE CREEK | 20,655 | 84 km |
| 2008 | COLD SPRINGS | 8,966 | 94 km |
| 2022 | GOAT ROCKS | 6,658 | 72 km |
| 2018 | MIRIAM | 5,719 | 87 km |
| 2009 | DISCOVERY | 4,240 | 98 km |
| 2017 | AMERICAN | 3,794 | 99 km |
| 2022 | SIOUXON | 2,551 | 72 km |
| 2022 | NAKIA CREEK | 1,737 | 93 km |
| 2013 | CONRAD LAKE | 1,106 | 92 km |
Source: NIFC/IRWIN Wildfire Records (100+ acres).
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 39°F (4°C) | 8.1 in | |
| February | 41°F (5°C) | 5.8 in | |
| March | 45°F (7°C) | 6.3 in | |
| April | 49°F (10°C) | 5.5 in | |
| May | 56°F (13°C) | 3.8 in | |
| June | 60°F (16°C) | 2.7 in | |
| July | 66°F (19°C) | 0.9 in | Driest |
| August | 66°F (19°C) | 1.3 in | Warmest |
| September | 61°F (16°C) | 2.5 in | |
| October | 52°F (11°C) | 5.4 in | |
| November | 44°F (7°C) | 8.4 in | Wettest |
| December | 39°F (4°C) | 8.1 in | Coldest |
Mossyrock has a seasonal temperature swing of 28°F / from 39°F in December to 66°F in August. Total annual precipitation is 58.7 inches, with November being the wettest month (8.4") and July the driest (0.9").