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Weather & Climate in Duncan, BC
Temperature, precipitation, air quality, natural hazards, and monthly weather data.
Duncan experiences four distinct seasons with an average annual temperature of 51°F (11°C). Winters average 40°F in January while summers reach 68°F in July. The area gets 228 sunny days per year, above the national average. Annual precipitation totals 49.8 inches (wetter than the 38-inch national average). The area receives 37.4 inches of snow annually, a moderate snowfall amount. The city sits at an elevation of 46 feet.
Temperature
40°F Jan (4°C)
68°F Jul (20°C)
| Annual Average | 51.2°F |
| 5% below US avg | |
| January Average | 40°F (4°C) |
| July Average | 68°F (20°C) |
| Sunny Days | 228 days/yr |
Geography
| Elevation | 46 ft (14 m) |
| Area | 0.8 sq mi (2.1 km²) |
| Population Density | 6,331/sq mi |
| Coordinates | 48.7829°N, 123.7027°W |
| Timezone | America/Vancouver |
Precipitation & Snow
Air Quality
Earthquake History
407 earthquakes (M2.5+) recorded within 150 km since 1990. Strongest on record: M5.0.
| Apr 14, 1990 | 4 km ENE of Deming, Washington | M5.0 | 113 km | 12 km |
| Apr 25, 2003 | 26 km W of Brinnon, Washington | M4.8 | 128 km | 51 km |
| Feb 21, 2025 | 28 km W of Squamish, Canada | M4.8 | 102 km | 10 km |
| Jan 8, 2015 | 19 km E of Tofino, Canada | M4.8 | 148 km | 25 km |
| Jan 30, 2009 | 6 km ESE of Lofall, Washington | M4.7 | 138 km | 62 km |
| Jan 24, 2020 | 46 km WNW of Neah Bay, Washington | M4.5 | 112 km | 10 km |
| Mar 3, 2025 | 2025 Orcas Island, Washington | M4.5 | 69 km | 16 km |
| Jun 24, 1997 | 19 km SSW of Gibsons, Canada | M4.4 | 51 km | 3 km |
| Apr 2, 1990 | 2 km ENE of Deming, Washington | M4.3 | 111 km | 0 km |
| Feb 19, 1991 | 31 km E of Squamish, Canada | M4.3 | 124 km | 5 km |
| Jan 23, 2001 | 9 km NNW of Ucluelet, Canada | M4.3 | 139 km | 10 km |
| Sep 21, 2002 | 9 km SW of Friday Harbor, Washington | M4.1 | 54 km | 23 km |
| Feb 22, 1996 | 31 km NNE of South Pender Harbour, Canada | M4.1 | 125 km | 2 km |
| Apr 3, 1990 | 3 km ENE of Deming, Washington | M4.0 | 112 km | 1 km |
| Apr 14, 1990 | 2 km ESE of Deming, Washington | M4.0 | 111 km | 3 km |
| Dec 27, 2012 | 12 km E of North Saanich, Canada | M4.0 | 36 km | 54 km |
| Sep 26, 2024 | 12 km E of Saanichton, Canada | M4.0 | 40 km | 52 km |
| Jul 1, 2009 | 4 km SE of Coupeville, Washington | M4.0 | 102 km | 58 km |
| Apr 7, 2001 | 36 km NNW of Neah Bay, Washington | M3.9 | 77 km | 32 km |
| Nov 20, 1994 | 26 km N of Ucluelet, Canada | M3.9 | 141 km | 38 km |
Source: USGS Earthquake Catalog (M2.5+, 1990–2025). Sorted by magnitude.
Tsunami History
4 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 | — | 145 km |
| 1946 | BRITISH COLUMBIA | Eruption + Earthquake | 9.0 m | 1 | 150 km |
| 1891 | WASHINGTON | Eruption + Earthquake | 2.4 m | — | 88 km |
| 1820 | CAMANO ISLAND, WA | Meteorological | — | — | 128 km |
Source: NOAA/NCEI Historical Tsunami Database.
Nearby Volcanoes
4 volcanoes within 200 km. Closest: Garibaldi (129 km).
| Name | Type | Elevation | Last Eruption | Distance |
| Garibaldi | Stratovolcano | 2,678 m (8,786 ft) | -8060 | 129 km |
| Garibaldi Lake | Volcanic field | 2,316 m (7,598 ft) | Unknown | 138 km |
| Baker | Stratovolcano(es) | 3,285 m (10,778 ft) | 1880 | 139 km |
| Cayley Volcanic Field | Volcanic field | 2,375 m (7,792 ft) | Unknown | 152 km |
Source: Smithsonian Institution Global Volcanism Program (GVP).
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 40°F (4°C) | 10.0 in | Wettest |
| February | 39°F (4°C) | 6.1 in | |
| March | 42°F (5°C) | 5.7 in | |
| April | 46°F (8°C) | 3.6 in | |
| May | 52°F (11°C) | 2.3 in | |
| June | 57°F (14°C) | 1.8 in | |
| July | 68°F (20°C) | 1.1 in | Warmest, Driest |
| August | 62°F (17°C) | 1.5 in | |
| September | 57°F (14°C) | 1.7 in | |
| October | 49°F (9°C) | 5.6 in | |
| November | 41°F (5°C) | 9.7 in | |
| December | 37°F (3°C) | 9.6 in | Coldest |
Duncan has a seasonal temperature swing of 32°F / from 37°F in December to 68°F in July. Total annual precipitation is 58.4 inches, with January being the wettest month (10.0") and July the driest (1.1").