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Weather & Climate in West Branch, IA
Temperature, precipitation, air quality, natural hazards, and monthly weather data.
West Branch experiences four distinct seasons with an average annual temperature of 49°F (10°C). Winters average 20°F in January while summers reach 74°F in July. The area gets 275 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 36.5 inches. Air quality is rated Good with a median AQI of 43. The city sits at an elevation of 740 feet.
Temperature
20°F Jan (-7°C)
74°F Jul (23°C)
| Annual Average | 49.3°F |
| 9% below US avg | |
| January Average | 20°F (-7°C) |
| July Average | 74°F (23°C) |
| Sunny Days | 275 days/yr |
Geography
| Elevation | 740 ft (226 m) |
| Area | 3.2 sq mi (8.3 km²) |
| Population Density | 983/sq mi |
| Coordinates | 41.6662°N, 91.3442°W |
| Timezone | America/Chicago |
| County | Johnson County County |
| Nearest Airport | The Eastern Iowa (CID) 24 miles away |
Precipitation & Snow
Air Quality
| AQI Median | 43.0 |
| Rating | Good |
Natural Hazard Risk
| Overall Risk | Relatively Moderate |
| Risk Score | 87.4 / 100 |
| Social Vulnerability | 11.4 / 100 |
| Community Resilience | 96.7 / 100 |
Hazard Breakdown
| Tornado | Relatively High |
| Hurricane | Very Low |
| Earthquake | Very Low |
| Wildfire | Relatively Low |
| Flood | Relatively Moderate |
| Hail | Relatively High |
| Strong Wind | Very High |
| Heat Wave | Relatively Moderate |
| Winter Weather | Relatively High |
| Lightning | Relatively Moderate |
| Ice Storm | Relatively Moderate |
| Drought | Relatively Moderate |
| Cold Wave | Relatively High |
| Landslide | Relatively Low |
Source: FEMA National Risk Index v1.20 (Dec 2025)
Tornado History
670 tornadoes (EF0+) recorded within 100 km since 1950. Strongest on record: EF4. Total: 6 fatalities, 309 injuries.
| Date | Rating | Distance | Path | Fatalities |
| Mar 31, 2023 | EF4 | 70 km | 19.9 mi | 0 |
| Mar 13, 1990 | EF4 | 63 km | 19.0 mi | 0 |
| Aug 12, 1974 | EF4 | 77 km | 5.0 mi | 0 |
| Aug 12, 1974 | EF4 | 70 km | 2.0 mi | 0 |
| Aug 26, 1965 | EF4 | 100 km | 4.7 mi | 1 |
| Apr 11, 1965 | EF4 | 40 km | 91.5 mi | 1 |
| Apr 30, 1954 | EF4 | 59 km | 80.4 mi | 0 |
| Jun 1, 2007 | EF3 | 46 km | 15.8 mi | 0 |
| May 21, 2004 | EF3 | 58 km | 3.0 mi | 0 |
| May 15, 1998 | EF3 | 54 km | 47.0 mi | 0 |
| May 9, 1995 | EF3 | 41 km | 10.0 mi | 0 |
| Jun 19, 1993 | EF3 | 89 km | 14.0 mi | 0 |
| Jun 19, 1993 | EF3 | 85 km | 9.0 mi | 0 |
| Jul 13, 1992 | EF3 | 60 km | 5.0 mi | 0 |
| Mar 13, 1990 | EF3 | 89 km | 15.5 mi | 0 |
| May 8, 1988 | EF3 | 48 km | 32.0 mi | 0 |
| Aug 15, 1978 | EF3 | 64 km | 6.4 mi | 0 |
| Jun 20, 1974 | EF3 | 96 km | 10.6 mi | 1 |
| Jun 14, 1974 | EF3 | 65 km | 48.6 mi | 0 |
| May 13, 1974 | EF3 | 62 km | 3.6 mi | 0 |
Source: NOAA Storm Prediction Center (EF0+, 1950–2024, US only).
Wildfire History
9 wildfires (100+ acres) recorded within 100 km. Largest: UNIT 3 (1,206 acres, 1999).
| Year | Name | Acres Burned | Distance |
| 1999 | UNIT 3 | 1,206 | 65 km |
| 2002 | HSB 03 2 | 1,130 | 65 km |
| 2009 | UNNAMED | 939 | 79 km |
| 2010 | FOLEY | 786 | 76 km |
| 2000 | DESTRUST A | 756 | 64 km |
| 2011 | ACE AUTO | 676 | 66 km |
| 2006 | HSB 003 | 674 | 66 km |
| 2004 | HSB 009 | 608 | 64 km |
| 2011 | IRCP WUI ROFAE #2 FY11 | 510 | 86 km |
Source: NIFC/IRWIN Wildfire Records (100+ acres).
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 20°F (-7°C) | 1.2 in | Coldest |
| February | 26°F (-3°C) | 1.1 in | Driest |
| March | 38°F (3°C) | 2.4 in | |
| April | 51°F (10°C) | 3.6 in | |
| May | 62°F (17°C) | 4.1 in | |
| June | 71°F (22°C) | 4.4 in | |
| July | 74°F (23°C) | 4.5 in | Warmest, Wettest |
| August | 73°F (23°C) | 4.2 in | |
| September | 65°F (18°C) | 4.1 in | |
| October | 53°F (12°C) | 2.9 in | |
| November | 38°F (4°C) | 2.2 in | |
| December | 25°F (-4°C) | 1.8 in |
West Branch has a seasonal temperature swing of 54°F / from 20°F in January to 74°F in July. Total annual precipitation is 36.4 inches, with July being the wettest month (4.5") and February the driest (1.1").