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Weather & Climate in Deep River, IA
Temperature, precipitation, air quality, natural hazards, and monthly weather data.
Deep River experiences four distinct seasons with an average annual temperature of 48°F (9°C). Winters average 19°F in January while summers reach 73°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 36.0 inches. The area receives 27.9 inches of snow annually, a moderate snowfall amount. Air quality is rated Good with a median AQI of 43. The city sits at an elevation of 908 feet.
Temperature
19°F Jan (-7°C)
73°F Jul (23°C)
| Annual Average | 48.2°F |
| 11% below US avg | |
| January Average | 19°F (-7°C) |
| July Average | 73°F (23°C) |
| Sunny Days | 275 days/yr |
Geography
| Elevation | 908 ft (277 m) |
| Area | 0.4 sq mi (1.1 km²) |
| Population Density | 716/sq mi |
| Coordinates | 41.5816°N, 92.3729°W |
| Timezone | America/Chicago |
| County | Poweshiek County County |
| Nearest Airport | Ottumwa Regional (OTM) 33 miles away |
Precipitation & Snow
Air Quality
| AQI Median | 43.0 |
| Rating | Good |
Natural Hazard Risk
| Overall Risk | Very Low |
| Risk Score | 31.3 / 100 |
| Social Vulnerability | 21.4 / 100 |
| Community Resilience | 84.9 / 100 |
Hazard Breakdown
| Tornado | Relatively Low |
| Hurricane | Very Low |
| Earthquake | Very Low |
| Wildfire | Very Low |
| Flood | Very Low |
| Hail | Relatively Moderate |
| Strong Wind | Relatively Moderate |
| Heat Wave | Relatively Low |
| Winter Weather | Relatively Low |
| Lightning | Very Low |
| Ice Storm | Relatively Low |
| Drought | Relatively High |
| Cold Wave | Relatively Low |
| Landslide | Relatively Low |
Source: FEMA National Risk Index v1.20 (Dec 2025)
Tornado History
599 tornadoes (EF0+) recorded within 100 km since 1950. Strongest on record: EF4. Total: 15 fatalities, 342 injuries.
| Date | Rating | Distance | Path | Fatalities |
| Mar 31, 2023 | EF4 | 42 km | 19.9 mi | 0 |
| Aug 12, 1974 | EF4 | 25 km | 2.0 mi | 0 |
| Aug 26, 1965 | EF4 | 81 km | 4.7 mi | 1 |
| Apr 30, 1954 | EF4 | 77 km | 80.4 mi | 0 |
| Mar 31, 2023 | EF3 | 58 km | 26.1 mi | 0 |
| Jul 19, 2018 | EF3 | 49 km | 9.2 mi | 0 |
| Jul 19, 2018 | EF3 | 78 km | 8.4 mi | 0 |
| Jun 22, 2015 | EF3 | 77 km | 11.1 mi | 0 |
| May 21, 2004 | EF3 | 69 km | 3.0 mi | 0 |
| Apr 8, 1999 | EF3 | 93 km | 16.0 mi | 0 |
| May 15, 1998 | EF3 | 63 km | 47.0 mi | 0 |
| Mar 13, 1990 | EF3 | 97 km | 9.0 mi | 0 |
| Sep 16, 1978 | EF3 | 80 km | 31.8 mi | 6 |
| May 4, 1977 | EF3 | 63 km | 17.8 mi | 0 |
| Nov 9, 1975 | EF3 | 69 km | 39.4 mi | 0 |
| May 31, 1971 | EF3 | 58 km | 9.4 mi | 0 |
| May 18, 1971 | EF3 | 63 km | 4.3 mi | 0 |
| May 18, 1971 | EF3 | 43 km | 4.3 mi | 0 |
| Apr 21, 1967 | EF3 | 75 km | 0.1 mi | 0 |
| Jan 24, 1967 | EF3 | 83 km | 25.0 mi | 0 |
Source: NOAA Storm Prediction Center (EF0+, 1950–2024, US only).
Wildfire History
5 wildfires (100+ acres) recorded within 100 km. Largest: NEAL SMITH WUI 2016 1 (1,050 acres, 2016).
| Year | Name | Acres Burned | Distance |
| 2016 | NEAL SMITH WUI 2016 1 | 1,050 | 76 km |
| 2009 | UNNAMED | 939 | 33 km |
| 2010 | FOLEY | 786 | 33 km |
| 2011 | ACE AUTO | 676 | 35 km |
| 2011 | IRCP WUI ROFAE #2 FY11 | 510 | 35 km |
Source: NIFC/IRWIN Wildfire Records (100+ acres).
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 19°F (-7°C) | 1.0 in | Coldest |
| February | 25°F (-4°C) | 0.9 in | Driest |
| March | 37°F (3°C) | 2.3 in | |
| April | 50°F (10°C) | 3.6 in | |
| May | 61°F (16°C) | 4.1 in | |
| June | 71°F (21°C) | 4.4 in | |
| July | 73°F (23°C) | 4.5 in | Warmest, Wettest |
| August | 72°F (22°C) | 4.2 in | |
| September | 64°F (18°C) | 4.2 in | |
| October | 52°F (11°C) | 2.8 in | |
| November | 37°F (3°C) | 2.3 in | |
| December | 25°F (-4°C) | 1.4 in |
Deep River has a seasonal temperature swing of 54°F / from 19°F in January to 73°F in July. Total annual precipitation is 35.5 inches, with July being the wettest month (4.5") and February the driest (0.9").