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Weather & Climate in Monmouth, OR
Temperature, precipitation, air quality, natural hazards, and monthly weather data.
Monmouth experiences four distinct seasons with an average annual temperature of 53°F (12°C). Winters average 41°F in January while summers reach 67°F in July. The area gets 251 sunny days per year, above the national average. Annual precipitation totals 47.8 inches (wetter than the 38-inch national average). Air quality is rated Good with a median AQI of 32. The city sits at an elevation of 201 feet.
Temperature
41°F Jan (5°C)
67°F Jul (20°C)
| Annual Average | 53.1°F |
| 2% below US avg | |
| January Average | 41°F (5°C) |
| July Average | 67°F (20°C) |
| Sunny Days | 251 days/yr |
Geography
| Elevation | 201 ft (61 m) |
| Area | 2.2 sq mi (5.8 km²) |
| Population Density | 4,989/sq mi |
| Coordinates | 44.8513°N, 123.2286°W |
| Timezone | America/Los_Angeles |
| County | Polk County County |
| Nearest Airport | Mahlon Sweet Field (EUG) 50 miles away |
Precipitation & Snow
Air Quality
| AQI Median | 32.0 |
| Rating | Good |
Natural Hazard Risk
| Overall Risk | Relatively Low |
| Risk Score | 72.8 / 100 |
| Social Vulnerability | 18.2 / 100 |
| Community Resilience | 64.5 / 100 |
Hazard Breakdown
| Tornado | Very Low |
| Earthquake | Relatively Moderate |
| Wildfire | Very Low |
| Flood | Relatively Low |
| Hail | Very Low |
| Strong Wind | Very Low |
| Heat Wave | Relatively Moderate |
| Winter Weather | Relatively Low |
| Lightning | Relatively Low |
| Ice Storm | Relatively Moderate |
| Drought | Very Low |
| Cold Wave | Very Low |
| Landslide | Relatively Low |
| Coastal Flood | No Rating |
| Volcano | Very Low |
| Avalanche | Very Low |
Source: FEMA National Risk Index v1.20 (Dec 2025)
Earthquake History
183 earthquakes (M2.5+) recorded within 150 km since 1990. Strongest on record: M5.6.
| Mar 25, 1993 | 4 km E of Scotts Mills, Oregon | M5.6 | 53 km | 20 km |
| Jul 12, 2004 | 30 km W of Yachats, Oregon | M4.9 | 115 km | 29 km |
| Aug 19, 2004 | 19 km W of Newport, Oregon | M4.7 | 87 km | 27 km |
| Jun 29, 2002 | 6 km ENE of Government Camp, Oregon | M4.5 | 133 km | 5 km |
| Jul 4, 2015 | 16 km ENE of Springfield, Oregon | M4.1 | 90 km | 8 km |
| Jun 6, 2021 | 6 km NE of Government Camp, Oregon | M3.9 | 132 km | 4 km |
| Apr 24, 2003 | 3 km NW of North Portland, Oregon | M3.9 | 95 km | 17 km |
| Apr 15, 2017 | 43 km WNW of Yachats, Oregon | M3.9 | 119 km | 38 km |
| Feb 8, 1995 | 9 km ESE of Hubbard, Oregon | M3.8 | 52 km | 24 km |
| Aug 3, 2006 | 2 km WNW of Cherry Grove, Washington | M3.8 | 116 km | 14 km |
| Jun 29, 2002 | 7 km NE of Government Camp, Oregon | M3.8 | 133 km | 5 km |
| Mar 20, 2012 | 29 km WNW of Yachats, Oregon | M3.7 | 110 km | 33 km |
| Jun 8, 1993 | 5 km ESE of Scotts Mills, Oregon | M3.7 | 54 km | 19 km |
| Jan 31, 2013 | 3 km ENE of Amboy, Washington | M3.7 | 135 km | 6 km |
| Feb 24, 1999 | 8 km WSW of Molalla, Oregon | M3.6 | 53 km | 34 km |
| Jul 3, 1992 | 57 km W of Waldport, Oregon | M3.6 | 128 km | 21 km |
| May 19, 2019 | 3 km ESE of Rose Lodge, Oregon | M3.6 | 51 km | 44 km |
| Sep 8, 2012 | 8 km N of Scotts Mills, Oregon | M3.5 | 52 km | 24 km |
| Aug 2, 1996 | 4 km S of Scotts Mills, Oregon | M3.5 | 47 km | 29 km |
| Oct 19, 1990 | 6 km NE of Government Camp, Oregon | M3.5 | 133 km | 5 km |
Source: USGS Earthquake Catalog (M2.5+, 1990-2025). Sorted by magnitude.
Tornado History
55 tornadoes (EF0+) recorded within 100 km since 1950. Strongest on record: EF3. Total: 6 fatalities, 302 injuries.
| Date | Rating | Distance | Path | Fatalities |
| Apr 5, 1972 | EF3 | 96 km | 8.7 mi | 6 |
| Dec 14, 2010 | EF2 | 28 km | 5.0 mi | 0 |
| Dec 8, 1993 | EF2 | 52 km | 6.0 mi | 0 |
| Sep 1, 2017 | EF1 | 51 km | 0.7 mi | 0 |
| Jun 13, 2013 | EF1 | 41 km | 0.3 mi | 0 |
| Jun 21, 2003 | EF1 | 4 km | 0.3 mi | 0 |
| Oct 9, 2000 | EF1 | 73 km | 0.1 mi | 0 |
| Oct 9, 2000 | EF1 | 58 km | 0.1 mi | 0 |
| Nov 12, 1991 | EF1 | 69 km | 0.2 mi | 0 |
| Nov 24, 1989 | EF1 | 95 km | 0.3 mi | 0 |
| Dec 12, 1975 | EF1 | 83 km | 2.0 mi | 0 |
| Mar 8, 1960 | EF1 | 29 km | 1.0 mi | 0 |
| Apr 12, 1957 | EF1 | 96 km | 2.5 mi | 0 |
| Dec 6, 1951 | EF1 | 75 km | 0.3 mi | 0 |
| Oct 31, 2024 | EF0 | 69 km | 0.2 mi | 0 |
| Jun 18, 2023 | EF0 | 63 km | 0.3 mi | 0 |
| Oct 24, 2022 | EF0 | 43 km | 0.0 mi | 0 |
| Jun 13, 2020 | EF0 | 86 km | 2.0 mi | 0 |
| Sep 8, 2019 | EF0 | 89 km | 0.1 mi | 0 |
| Jul 1, 2019 | EF0 | 91 km | 1.6 mi | 0 |
Source: NOAA Storm Prediction Center (EF0+, 1950-2024, US only).
Tsunami History
1 tsunami recorded within 500 km.
| Year | Location | Cause | Max Wave | Deaths | Distance |
| 1700 | CASCADIA SUBDUCTION ZONE | Earthquake | - | 2 | 140 km |
Source: NOAA/NCEI Historical Tsunami Database.
Nearby Volcanoes
10 volcanoes within 200 km. Closest: Jefferson (115 km).
| Name | Type | Elevation | Last Eruption | Distance |
| Jefferson | Stratovolcano | 3,199 m (10,495 ft) | 950 | 115 km |
| Sand Mountain Field | Pyroclastic cone(s) | 1,664 m (5,459 ft) | -950 | 115 km |
| Belknap | Shield(s) | 2,095 m (6,873 ft) | 480 | 127 km |
| Hood | Stratovolcano | 3,426 m (11,240 ft) | 1866 | 134 km |
| Three Sisters | Complex | 3,159 m (10,364 ft) | 440 | 141 km |
| West Crater | Volcanic field | 1,329 m (4,360 ft) | -5750 | 145 km |
| Bachelor | Stratovolcano | 2,763 m (9,065 ft) | -5800 | 156 km |
| Indian Heaven | Shield(s) | 1,806 m (5,925 ft) | -6250 | 163 km |
| St. Helens | Stratovolcano | 2,549 m (8,363 ft) | 2008 | 171 km |
| Davis Lake | Volcanic field | 2,163 m (7,096 ft) | -2790 | 181 km |
Source: Smithsonian Institution Global Volcanism Program (GVP).
Wildfire History
13 wildfires (100+ acres) recorded within 100 km. Largest: BEACHIE CREEK (194,619 acres, 2020).
| Year | Name | Acres Burned | Distance |
| 2020 | BEACHIE CREEK | 194,619 | 67 km |
| 2020 | HOLIDAY FARM | 174,390 | 96 km |
| 2020 | RIVERSIDE | 138,190 | 85 km |
| 2021 | BULL COMPLEX | 26,233 | 94 km |
| 2014 | 36 PIT | 5,838 | 90 km |
| 1987 | ROCKHOUSE | 5,011 | 22 km |
| 2011 | MOTHER LODE | 2,881 | 89 km |
| 2010 | BULL OF THE WOODS | 2,535 | 93 km |
| 2020 | ECHO MTN COMPLEX | 2,161 | 58 km |
| 1999 | AUSTA | 1,525 | 100 km |
| 2020 | DOWTY RD | 1,424 | 85 km |
| 1987 | 87552212 | 1,166 | 13 km |
| 1987 | 87791147 | 1,048 | 83 km |
Source: NIFC/IRWIN Wildfire Records (100+ acres).
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 41°F (5°C) | 7.9 in | |
| February | 43°F (6°C) | 6.3 in | |
| March | 47°F (8°C) | 5.6 in | |
| April | 50°F (10°C) | 3.1 in | |
| May | 55°F (13°C) | 2.1 in | |
| June | 60°F (16°C) | 1.3 in | |
| July | 67°F (20°C) | 0.6 in | Warmest, Driest |
| August | 66°F (19°C) | 0.8 in | |
| September | 62°F (17°C) | 1.6 in | |
| October | 53°F (12°C) | 3.5 in | |
| November | 45°F (7°C) | 7.7 in | |
| December | 40°F (4°C) | 8.9 in | Coldest, Wettest |
Monmouth has a seasonal temperature swing of 27°F / from 40°F in December to 67°F in July. Total annual precipitation is 49.4 inches, with December being the wettest month (8.9") and July the driest (0.6").