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Weather & Climate in Mermentau, LA
Temperature, precipitation, air quality, natural hazards, and monthly weather data.
Mermentau enjoys a temperate climate with an average annual temperature of 68°F (20°C). Winters average 51°F in January while summers reach 82°F in July. The area gets 313 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 63.5 inches (wetter than the 38-inch national average). Air quality is rated Good with a median AQI of 42. The city sits at an elevation of 11 feet.
Temperature
51°F Jan (11°C)
82°F Jul (28°C)
| Annual Average | 67.8°F |
| 26% above US avg | |
| January Average | 51°F (11°C) |
| July Average | 82°F (28°C) |
| Sunny Days | 313 days/yr |
Geography
| Elevation | 11 ft (3 m) |
| Area | 0.9 sq mi (2.3 km²) |
| Population Density | 268/sq mi |
| Coordinates | 30.1880°N, 92.5838°W |
| Timezone | America/Chicago |
| County | Acadia Parish County |
| Nearest Airport | Chennault International (CWF) 33 miles away |
Precipitation & Snow
Air Quality
| AQI Median | 42.0 |
| Rating | Good |
Natural Hazard Risk
| Overall Risk | Relatively Moderate |
| Risk Score | 88.6 / 100 |
| Social Vulnerability | 86.7 / 100 |
| Community Resilience | 30.3 / 100 |
Hazard Breakdown
| Tornado | Relatively Moderate |
| Hurricane | Relatively High |
| Earthquake | Very Low |
| Wildfire | Very Low |
| Flood | Relatively Moderate |
| Hail | Relatively Low |
| Strong Wind | Relatively Low |
| Heat Wave | Relatively Moderate |
| Winter Weather | Relatively Low |
| Lightning | Relatively High |
| Ice Storm | Relatively Moderate |
| Drought | Relatively High |
| Cold Wave | Relatively Moderate |
| Landslide | Very Low |
| Coastal Flood | Relatively Low |
Source: FEMA National Risk Index v1.20 (Dec 2025)
Hurricane History
23 hurricanes (Category 1+) recorded within 500 km since 1980. Strongest on record: Category 4.
| Year | Name | Category | Max Wind | Closest |
| 2024 | Francine | Category 2 | 104 mph | 159 km |
| 2021 | Ida | Category 4 | 150 mph | 177 km |
| 2020 | Laura | Category 4 | 150 mph | 81 km |
| 2020 | Zeta | Category 3 | 115 mph | 221 km |
| 2020 | Delta | Category 3 | 115 mph | 32 km |
| 2019 | Barry | Category 1 | 75 mph | 75 km |
| 2012 | Isaac | Category 1 | 81 mph | 219 km |
| 2008 | Ike | Category 2 | 109 mph | 227 km |
| 2008 | Gustav | Category 2 | 109 mph | 67 km |
| 2007 | Humberto | Category 1 | 92 mph | 98 km |
| 2005 | Katrina | Category 4 | 144 mph | 287 km |
| 2005 | Rita | Category 3 | 127 mph | 121 km |
| 2005 | Cindy | Category 1 | 75 mph | 264 km |
| 2002 | Lili | Category 3 | 121 mph | 34 km |
| 1997 | Danny | Category 1 | 75 mph | 282 km |
| 1992 | Andrew | Category 4 | 144 mph | 86 km |
| 1989 | Jerry | Category 1 | 86 mph | 258 km |
| 1989 | Chantal | Category 1 | 81 mph | 176 km |
| 1986 | Bonnie | Category 1 | 86 mph | 168 km |
| 1985 | Elena | Category 2 | — | 273 km |
Source: NOAA IBTrACS (Category 1+, 1980–2026).
Tornado History
635 tornadoes (EF0+) recorded within 100 km since 1950. Strongest on record: EF3. Total: 34 fatalities, 555 injuries.
| Date | Rating | Distance | Path | Fatalities |
| Apr 10, 2021 | EF3 | 80 km | 8.7 mi | 1 |
| May 17, 2020 | EF3 | 43 km | 3.9 mi | 1 |
| Dec 16, 2019 | EF3 | 98 km | 62.6 mi | 1 |
| Nov 21, 1992 | EF3 | 43 km | 6.0 mi | 0 |
| May 20, 1984 | EF3 | 86 km | 3.0 mi | 0 |
| Feb 9, 1983 | EF3 | 36 km | 3.0 mi | 0 |
| Feb 9, 1983 | EF3 | 45 km | 21.0 mi | 0 |
| Jan 31, 1983 | EF3 | 92 km | 5.0 mi | 1 |
| Jan 31, 1983 | EF3 | 36 km | 6.0 mi | 1 |
| Apr 21, 1977 | EF3 | 62 km | 3.8 mi | 1 |
| Oct 29, 1974 | EF3 | 14 km | 31.3 mi | 2 |
| Oct 29, 1974 | EF3 | 49 km | 7.3 mi | 0 |
| Apr 17, 1973 | EF3 | 57 km | 0.5 mi | 0 |
| Feb 12, 1971 | EF3 | 59 km | 3.6 mi | 0 |
| Dec 25, 1969 | EF3 | 37 km | 1.5 mi | 1 |
| May 1, 1967 | EF3 | 63 km | 5.2 mi | 0 |
| Sep 10, 1961 | EF3 | 34 km | 5.7 mi | 1 |
| Nov 7, 1957 | EF3 | 41 km | 9.2 mi | 4 |
| Oct 15, 1957 | EF3 | 58 km | 37.9 mi | 1 |
| Apr 4, 1952 | EF3 | 28 km | 36.7 mi | 0 |
Source: NOAA Storm Prediction Center (EF0+, 1950–2024, US only).
Wildfire History
20 wildfires (100+ acres) recorded within 100 km. Largest: LASBR-BIL-FY23-RX-PRESCRIBED FIRE (18,392 acres, 2023).
| Year | Name | Acres Burned | Distance |
| 2023 | LASBR-BIL-FY23-RX-PRESCRIBED FIRE | 18,392 | 89 km |
| 2005 | LACASSINE POOL | 16,640 | 40 km |
| 2000 | UNNAMED | 12,496 | 63 km |
| 2011 | SABINE WEST - 2011 (UNIT 3) | 10,195 | 100 km |
| 2014 | PINTAIL | 9,498 | 92 km |
| 1987 | U 1 PF 87 09 | 8,953 | 91 km |
| 1998 | UNIT 1 RX | 8,913 | 94 km |
| 2006 | UNNAMED | 8,563 | 50 km |
| 2022 | NORTHLINE | 8,096 | 95 km |
| 2000 | RX 3 | 7,409 | 99 km |
| 2013 | LEONARD | 7,235 | 96 km |
| 2023 | HWY 113 | 7,104 | 93 km |
| 2005 | UNIT 3 | 6,764 | 95 km |
| 2005 | UNNAMED | 6,588 | 39 km |
| 2010 | CICADA | 6,380 | 95 km |
| 2009 | DOG HOUSE | 6,267 | 95 km |
| 2011 | GRAND FUE | 6,006 | 91 km |
| 2004 | UNIT 3-04-1W | 5,973 | 98 km |
| 1997 | UNIT 2 RX | 5,837 | 96 km |
| 2009 | TARGA | 5,697 | 98 km |
Source: NIFC/IRWIN Wildfire Records (100+ acres).
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 51°F (11°C) | 5.6 in | Coldest |
| February | 54°F (12°C) | 4.0 in | Driest |
| March | 61°F (16°C) | 4.4 in | |
| April | 67°F (20°C) | 4.1 in | |
| May | 75°F (24°C) | 5.6 in | |
| June | 80°F (27°C) | 5.4 in | |
| July | 82°F (28°C) | 5.7 in | Warmest, Wettest |
| August | 82°F (28°C) | 5.2 in | |
| September | 78°F (25°C) | 5.6 in | |
| October | 69°F (20°C) | 4.3 in | |
| November | 60°F (15°C) | 4.8 in | |
| December | 53°F (12°C) | 5.4 in |
Mermentau has a seasonal temperature swing of 31°F / from 51°F in January to 82°F in July. Total annual precipitation is 60.0 inches, with July being the wettest month (5.7") and February the driest (4.0").