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Weather & Climate in Waterloo, CA
Temperature, precipitation, air quality, natural hazards, and monthly weather data.
Waterloo enjoys a temperate climate with an average annual temperature of 62°F (17°C). Winters average 48°F in January while summers reach 76°F in July. The area gets 330 sunny days per year, well above the U.S. average of 205 / making it one of the sunnier locations in the country. Annual precipitation totals 18.4 inches (drier than the 38-inch national average). Air quality is rated Good with a median AQI of 48. The city sits at an elevation of 58 feet.
Temperature
48°F Jan (9°C)
76°F Jul (24°C)
| Annual Average | 62.2°F |
| 15% above US avg | |
| January Average | 48°F (9°C) |
| July Average | 76°F (24°C) |
| Sunny Days | 330 days/yr |
Geography
| Elevation | 58 ft (18 m) |
| Area | 5.4 sq mi (14.1 km²) |
| Population Density | 163/sq mi |
| Coordinates | 38.0365°N, 121.1846°W |
| Timezone | America/Los_Angeles |
| County | Sacramento County County |
| Nearest Airport | Sacramento International (SMF) 51 miles away |
Precipitation & Snow
Air Quality
| AQI Median | 48.0 |
| Rating | Good |
Natural Hazard Risk
| Overall Risk | Relatively High |
| Risk Score | 98.1 / 100 |
| Social Vulnerability | 37.4 / 100 |
| Community Resilience | 57.0 / 100 |
Hazard Breakdown
| Tornado | Relatively Moderate |
| Earthquake | Relatively High |
| Wildfire | Relatively Moderate |
| Flood | Relatively High |
| Hail | Relatively Low |
| Strong Wind | Very Low |
| Heat Wave | Relatively Moderate |
| Winter Weather | Very Low |
| Lightning | Relatively Moderate |
| Drought | Relatively High |
| Cold Wave | No Rating |
| Landslide | Relatively Low |
| Coastal Flood | No Rating |
| Volcano | Very Low |
Source: FEMA National Risk Index v1.20 (Dec 2025)
Earthquake History
3,343 earthquakes (M2.5+) recorded within 150 km since 1990. Strongest on record: M6.0.
| Aug 24, 2014 | The 2014 South Napa, California Earthquake | M6.0 | 101 km | 11 km |
| Apr 18, 1990 | 5 km NNW of Aromas, California | M5.4 | 130 km | 5 km |
| Apr 18, 1990 | 4 km E of Interlaken, California | M5.1 | 128 km | 7 km |
| Aug 12, 1998 | 10 km SW of Ridgemark, California | M5.1 | 145 km | 9 km |
| Jan 16, 1993 | 9 km E of Gilroy, California | M4.9 | 116 km | 7 km |
| Apr 19, 1996 | 2 km E of Aromas, California | M4.9 | 134 km | 5 km |
| May 14, 2002 | 5 km SSW of Gilroy, California | M4.9 | 124 km | 7 km |
| Apr 18, 1990 | 4 km NNW of Aromas, California | M4.9 | 130 km | 6 km |
| Sep 3, 2000 | 5 km WSW of Yountville, California | M4.9 | 114 km | 9 km |
| May 21, 1996 | 8 km ESE of East Foothills, California | M4.7 | 89 km | 8 km |
| Apr 18, 1990 | 4 km N of Aromas, California | M4.7 | 130 km | 4 km |
| Aug 11, 1993 | 14 km ESE of Alum Rock, California | M4.7 | 92 km | 9 km |
| Mar 24, 1991 | 1 km NNE of Interlaken, California | M4.6 | 128 km | 15 km |
| Aug 18, 1999 | 0 km S of Bolinas, California | M4.6 | 132 km | 8 km |
| Sep 19, 2023 | 15 km SW of Westley, CA | M4.5 | 67 km | 4 km |
| Aug 3, 2006 | 5 km W of Glen Ellen, California | M4.5 | 128 km | 9 km |
| Jan 12, 2011 | 9 km SSE of San Juan Bautista, California | M4.5 | 143 km | 8 km |
| Apr 4, 2023 | 1km NNW of Tres Pinos, CA | M4.4 | 138 km | 10 km |
| Apr 7, 1990 | 3 km SSE of North Gate, California | M4.4 | 72 km | 8 km |
| Apr 18, 1990 | 5 km E of Interlaken, California | M4.4 | 129 km | 7 km |
Source: USGS Earthquake Catalog (M2.5+, 1990–2025). Sorted by magnitude.
Tornado History
79 tornadoes (EF0+) recorded within 100 km since 1950. Strongest on record: EF2. Total: 3 injuries.
| Date | Rating | Distance | Path | Fatalities |
| Feb 7, 1978 | EF2 | 77 km | 1.9 mi | 0 |
| Apr 27, 1953 | EF2 | 46 km | 0.1 mi | 0 |
| Mar 11, 2023 | EF1 | 59 km | 0.8 mi | 0 |
| Jan 10, 2023 | EF1 | 38 km | 0.4 mi | 0 |
| Dec 24, 2015 | EF1 | 75 km | 6.2 mi | 0 |
| Nov 15, 2015 | EF1 | 65 km | 3.0 mi | 0 |
| Jan 23, 2010 | EF1 | 53 km | 1.6 mi | 0 |
| Apr 14, 2006 | EF1 | 46 km | 0.5 mi | 0 |
| Dec 16, 2002 | EF1 | 98 km | 1.3 mi | 0 |
| Dec 12, 1996 | EF1 | 42 km | 0.6 mi | 0 |
| Apr 19, 1988 | EF1 | 15 km | 0.2 mi | 0 |
| Apr 19, 1988 | EF1 | 72 km | 1.0 mi | 0 |
| Mar 22, 1983 | EF1 | 77 km | 2.0 mi | 0 |
| Jan 14, 1980 | EF1 | 87 km | 0.3 mi | 0 |
| Mar 4, 1978 | EF1 | 55 km | 2.5 mi | 0 |
| Mar 4, 1978 | EF1 | 75 km | 1.0 mi | 0 |
| Mar 1, 1978 | EF1 | 47 km | 1.5 mi | 0 |
| May 31, 1967 | EF1 | 13 km | 0.1 mi | 0 |
| Apr 1, 1958 | EF1 | 72 km | 2.0 mi | 0 |
| Jan 14, 2023 | EF0 | 32 km | 0.3 mi | 0 |
Source: NOAA Storm Prediction Center (EF0+, 1950–2024, US only).
Tsunami History
5 tsunamis recorded within 500 km. Highest wave on record: 4.5 m (15 ft).
| Year | Location | Cause | Max Wave | Deaths | Distance |
| 1868 | N. CALIFORNIA | Eruption + Earthquake | 4.5 m | 30 | 89 km |
| 1989 | N. CALIFORNIA | Earthquake | 1.0 m | 62 | 127 km |
| 1856 | N. CALIFORNIA | Eruption + Earthquake | 0.6 m | — | 115 km |
| 1906 | N. CALIFORNIA | Eruption + Earthquake | 0.1 m | — | 121 km |
| 1865 | N. CALIFORNIA | Eruption + Earthquake | — | — | 112 km |
Source: NOAA/NCEI Historical Tsunami Database.
Nearby Volcanoes
4 volcanoes within 200 km. Closest: Clear Lake (173 km).
| Name | Type | Elevation | Last Eruption | Distance |
| Clear Lake | Volcanic field | 1,439 m (4,721 ft) | Unknown | 173 km |
| Mono Lake Volcanic Field | Pyroclastic cone(s) | 2,121 m (6,959 ft) | 1790 | 189 km |
| Mono-Inyo Craters | Lava dome(s) | 2,796 m (9,173 ft) | 1380 | 191 km |
| Mammoth Mountain | Lava dome(s) | 3,369 m (11,053 ft) | 1260 | 194 km |
Source: Smithsonian Institution Global Volcanism Program (GVP).
Wildfire History
20 wildfires (100+ acres) recorded within 100 km. Largest: SCU LIGHTNING COMPLEX (405,787 acres, 2020).
| Year | Name | Acres Burned | Distance |
| 2020 | SCU LIGHTNING COMPLEX | 405,787 | 67 km |
| 2015 | BUTTE | 72,894 | 58 km |
| 2017 | ATLAS | 51,664 | 99 km |
| 1987 | PAPER | 49,296 | 93 km |
| 2007 | LICK | 47,424 | 93 km |
| 2006 | CANYON | 36,851 | 77 km |
| 1988 | MILLER | 35,750 | 91 km |
| 1992 | GULCH | 18,019 | 64 km |
| 1996 | ROGGE | 17,559 | 95 km |
| 2003 | ANNIE | 17,383 | 90 km |
| 2004 | POWER | 17,266 | 94 km |
| 2024 | CORRAL | 16,138 | 51 km |
| 2001 | DARBY | 14,734 | 79 km |
| 2018 | WAVERLY | 12,238 | 30 km |
| 2009 | CORRAL | 12,006 | 56 km |
| 2001 | CREEK | 9,793 | 88 km |
| 1992 | MOCCASIN | 9,565 | 81 km |
| 1996 | SCOTT | 8,828 | 60 km |
| 2015 | WRAGG | 8,455 | 92 km |
| 2009 | KNIGHT | 8,140 | 85 km |
Source: NIFC/IRWIN Wildfire Records (100+ acres).
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 48°F (9°C) | 3.5 in | Wettest |
| February | 51°F (11°C) | 3.0 in | |
| March | 55°F (13°C) | 2.9 in | |
| April | 59°F (15°C) | 1.1 in | |
| May | 66°F (19°C) | 0.5 in | |
| June | 71°F (22°C) | 0.1 in | |
| July | 76°F (24°C) | 0.1 in | Warmest, Driest |
| August | 74°F (23°C) | 0.1 in | |
| September | 71°F (21°C) | 0.3 in | |
| October | 63°F (17°C) | 1.0 in | |
| November | 53°F (11°C) | 2.4 in | |
| December | 45°F (7°C) | 2.5 in | Coldest |
Waterloo has a seasonal temperature swing of 31°F / from 45°F in December to 76°F in July. Total annual precipitation is 17.3 inches, with January being the wettest month (3.5") and July the driest (0.1").