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Weather & Climate in Oso, WA
Temperature, precipitation, air quality, natural hazards, and monthly weather data.
Oso experiences four distinct seasons with an average annual temperature of 50°F (10°C). Winters average 35°F in January while summers reach 66°F in July. The area gets 166 sunny days per year, below the national average of 205. Annual precipitation totals 83.1 inches (wetter than the 38-inch national average). Air quality is rated Good with a median AQI of 28 / among the cleanest air in the country. The city sits at an elevation of 338 feet.
Temperature
35°F Jan (2°C)
66°F Jul (19°C)
| Annual Average | 49.6°F |
| 8% below US avg | |
| January Average | 35°F (2°C) |
| July Average | 66°F (19°C) |
| Sunny Days | 166 days/yr |
Geography
| Elevation | 338 ft (103 m) |
| Area | 1.4 sq mi (3.7 km²) |
| Population Density | 143/sq mi |
| Coordinates | 48.2838°N, 121.9162°W |
| Timezone | America/Los_Angeles |
| County | Skagit County County |
| Nearest Airport | Skagit Regional (MVW) 27 miles away |
Precipitation & Snow
Air Quality
| AQI Median | 28.0 |
| Rating | Good |
Natural Hazard Risk
| Overall Risk | Relatively Moderate |
| Risk Score | 88.8 / 100 |
| Social Vulnerability | 31.7 / 100 |
| Community Resilience | 73.4 / 100 |
Hazard Breakdown
| Tornado | Very Low |
| Earthquake | Relatively Moderate |
| Wildfire | Very Low |
| Flood | Relatively Moderate |
| Hail | Very Low |
| Strong Wind | Very Low |
| Heat Wave | Relatively Low |
| Winter Weather | Relatively Moderate |
| Lightning | Relatively Low |
| Ice Storm | Relatively High |
| Drought | Very Low |
| Cold Wave | Relatively Low |
| Landslide | Relatively Moderate |
| Coastal Flood | Relatively High |
| Tsunami | Very Low |
| Volcano | Relatively High |
| Avalanche | Relatively Low |
Source: FEMA National Risk Index v1.20 (Dec 2025)
Earthquake History
683 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 | 140 km | 52 km |
| May 3, 1996 | 8 km NNE of Lake Marcel-Stillwater, Washington | M5.4 | 58 km | 4 km |
| Apr 14, 1990 | 4 km ENE of Deming, Washington | M5.0 | 65 km | 12 km |
| Jan 29, 1995 | 3 km WSW of Des Moines, Washington | M5.0 | 105 km | 15 km |
| Jun 23, 1997 | 2 km NE of Enetai, Washington | M4.9 | 91 km | 13 km |
| Apr 25, 2003 | 26 km W of Brinnon, Washington | M4.8 | 120 km | 51 km |
| Jan 30, 2009 | 6 km ESE of Lofall, Washington | M4.7 | 74 km | 62 km |
| Jul 12, 2019 | 2 km S of Roosevelt, Washington | M4.6 | 46 km | 29 km |
| Mar 3, 2025 | 2025 Orcas Island, Washington | M4.5 | 75 km | 16 km |
| Jun 18, 1994 | 11 km SE of Skykomish, Washington | M4.3 | 88 km | -1 km |
| Apr 2, 1990 | 2 km ENE of Deming, Washington | M4.3 | 64 km | 0 km |
| Jul 22, 2001 | 4 km WSW of DuPont, Washington | M4.3 | 145 km | 52 km |
| Jun 27, 2013 | 25 km N of Leavenworth, Washington | M4.3 | 105 km | 8 km |
| Feb 18, 2015 | 15 km ENE of Cle Elum, Washington | M4.2 | 144 km | 4 km |
| Sep 21, 2002 | 9 km SW of Friday Harbor, Washington | M4.1 | 92 km | 23 km |
| Feb 23, 2017 | 11 km NE of Hoodsport, Washington | M4.1 | 122 km | 15 km |
| Apr 14, 1990 | 2 km ESE of Deming, Washington | M4.0 | 63 km | 3 km |
| Apr 3, 1990 | 3 km ENE of Deming, Washington | M4.0 | 64 km | 1 km |
| Jun 15, 1994 | 1 km WNW of Hoodsport, Washington | M4.0 | 135 km | 44 km |
| Sep 26, 2024 | 12 km E of Saanichton, Canada | M4.0 | 104 km | 52 km |
Source: USGS Earthquake Catalog (M2.5+, 1990–2025). Sorted by magnitude.
Tornado History
13 tornadoes (EF0+) recorded within 100 km since 1950. Strongest on record: EF3. Total: 1 injury.
| Date | Rating | Distance | Path | Fatalities |
| Dec 12, 1969 | EF3 | 94 km | 3.8 mi | 0 |
| May 13, 1986 | EF2 | 12 km | 0.3 mi | 0 |
| Nov 24, 1970 | EF2 | 29 km | 0.3 mi | 0 |
| May 18, 2005 | EF1 | 26 km | 0.2 mi | 0 |
| Oct 26, 1971 | EF1 | 35 km | 3.0 mi | 0 |
| Sep 28, 1962 | EF1 | 92 km | 0.1 mi | 0 |
| Jun 16, 2006 | EF0 | 48 km | 0.5 mi | 0 |
| Jun 5, 2004 | EF0 | 25 km | 0.1 mi | 0 |
| Apr 27, 2004 | EF0 | 83 km | 2.7 mi | 0 |
| Jun 11, 2001 | EF0 | 88 km | — | 0 |
| Aug 24, 1997 | EF0 | 43 km | 0.5 mi | 0 |
| Apr 9, 1991 | EF0 | 92 km | 0.8 mi | 0 |
| Aug 18, 1964 | EF0 | 88 km | 5.2 mi | 0 |
Source: NOAA Storm Prediction Center (EF0+, 1950–2024, US only).
Tsunami History
6 tsunamis recorded within 500 km. Highest wave on record: 38.0 m (125 ft).
| Year | Location | Cause | Max Wave | Deaths | Distance |
| 2007 | CHEHALIS LAKE, CHILLIWACK | Meteorological | 38.0 m | — | 132 km |
| 1894 | PUYALLUP RIVER DELTA, TACOMA, WA | Meteorological | 3.0 m | 2 | 118 km |
| 1891 | WASHINGTON | Eruption + Earthquake | 2.4 m | — | 122 km |
| 1949 | PUGET SOUND, WA | Meteorological | 2.4 m | — | 119 km |
| 1949 | PUGET SOUND, WA | Eruption + Earthquake | — | 8 | 135 km |
| 1820 | CAMANO ISLAND, WA | Meteorological | — | — | 41 km |
Source: NOAA/NCEI Historical Tsunami Database.
Nearby Volcanoes
5 volcanoes within 200 km. Closest: Baker (55 km).
| Name | Type | Elevation | Last Eruption | Distance |
| Baker | Stratovolcano(es) | 3,285 m (10,778 ft) | 1880 | 55 km |
| Glacier Peak | Stratovolcano | 3,213 m (10,541 ft) | 1700 | 63 km |
| Rainier | Stratovolcano | 4,392 m (14,409 ft) | 1450 | 160 km |
| Garibaldi | Stratovolcano | 2,678 m (8,786 ft) | -8060 | 191 km |
| Garibaldi Lake | Volcanic field | 2,316 m (7,598 ft) | Unknown | 200 km |
Source: Smithsonian Institution Global Volcanism Program (GVP).
Wildfire History
20 wildfires (100+ acres) recorded within 100 km. Largest: WOLVERINE (66,329 acres, 2015).
| Year | Name | Acres Burned | Distance |
| 2015 | WOLVERINE | 66,329 | 95 km |
| 2022 | BOLT CREEK | 15,211 | 69 km |
| 2007 | DOMKE LAKE COMPLEX | 10,090 | 99 km |
| 2006 | TINPAN | 9,044 | 92 km |
| 2023 | AIRPLANE LAKE | 7,576 | 71 km |
| 2023 | SOURDOUGH | 7,517 | 76 km |
| 2006 | FLICK CREEK | 6,990 | 97 km |
| 2015 | GOODELL | 6,624 | 68 km |
| 1994 | BUTTE CK2 | 6,489 | 98 km |
| 2022 | MINNOW RIDGE | 5,458 | 99 km |
| 2022 | SUIATTLE RIVER | 4,400 | 40 km |
| 2016 | BUCK CREEK | 4,199 | 79 km |
| 2022 | IRVING PEAK | 3,983 | 80 km |
| 2022 | COPPER LAKE | 3,825 | 83 km |
| 2010 | RAINBOW BRIDGE | 3,634 | 91 km |
| 2022 | BRUSH CREEK 2 | 3,186 | 79 km |
| 2003 | MINERAL PARK | 3,010 | 62 km |
| 2022 | SILESIA | 2,737 | 79 km |
| 2022 | MCALLISTER CREEK | 2,581 | 72 km |
| 2014 | LONE MOUNTAIN 1 | 2,578 | 97 km |
Source: NIFC/IRWIN Wildfire Records (100+ acres).
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 35°F (2°C) | 9.7 in | Coldest |
| February | 38°F (3°C) | 7.2 in | |
| March | 41°F (5°C) | 7.1 in | |
| April | 45°F (7°C) | 5.3 in | |
| May | 51°F (11°C) | 4.0 in | |
| June | 56°F (13°C) | 3.1 in | |
| July | 66°F (19°C) | 1.9 in | Warmest, Driest |
| August | 62°F (16°C) | 2.1 in | |
| September | 57°F (14°C) | 3.7 in | |
| October | 48°F (9°C) | 6.2 in | |
| November | 41°F (5°C) | 10.4 in | Wettest |
| December | 35°F (2°C) | 10.1 in |
Oso has a seasonal temperature swing of 30°F / from 35°F in January to 66°F in July. Total annual precipitation is 70.8 inches, with November being the wettest month (10.4") and July the driest (1.9").