Weather & Climate in Delmar, IA
Temperature, precipitation, air quality, natural hazards, and monthly weather data.
Delmar 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. Annual precipitation totals 36.7 inches. The area receives 30.3 inches of snow annually, a moderate snowfall amount. Air quality is rated Good with a median AQI of 46. 63% of days have good air quality. The city sits at an elevation of 811 feet.
Temperature
19°F Jan (-7°C)
73°F Jul (23°C)
| Annual Average | 47.9°F |
| 11% below US avg | |
| January Average | 19°F (-7°C) |
| July Average | 73°F (23°C) |
Geography
| Elevation | 811 ft (247 m) |
| Area | 0.8 sq mi (2.0 km²) |
| Population Density | 549/sq mi |
| Coordinates | 41.9989°N, 90.6079°W |
| Timezone | America/Chicago |
| County | Clinton County County |
| Nearest Airport | Dubuque Regional (DBQ) 28 miles away |
Precipitation & Snow
Air Quality
| AQI Median | 46.0 |
| Rating | Good |
| Good Days % | 63.0% |
| Unhealthy Days | 0 |
Natural Hazard Risk
| Overall Risk | Relatively Low |
| Risk Score | 64.8 / 100 |
| Social Vulnerability | 34.6 / 100 |
| Community Resilience | 87.5 / 100 |
Hazard Breakdown
| Tornado | Relatively Moderate |
| Hurricane | Very Low |
| Earthquake | Very Low |
| Wildfire | Very Low |
| Flood | Relatively Low |
| Hail | Relatively Moderate |
| Strong Wind | Relatively High |
| Heat Wave | Relatively Low |
| Winter Weather | Relatively Low |
| Lightning | Relatively Low |
| Ice Storm | Relatively Moderate |
| Drought | Relatively High |
| Cold Wave | Relatively Moderate |
| Landslide | Relatively Low |
Source: FEMA National Risk Index v1.20 (Dec 2025)
Earthquake History
1 earthquake (M2.5+) recorded within 150 km since 1990. Strongest on record: M3.5.
| Sep 2, 1999 | 8 km W of Amboy, Illinois | M3.5 | 102 km | 5 km |
Source: USGS Earthquake Catalog (M2.5+, 1990-2025). Sorted by magnitude.
Tornado History
650 tornadoes (EF0+) recorded within 100 km since 1950. Strongest on record: EF4. Total: 6 fatalities, 255 injuries.
| Date | Rating | Distance | Path | Fatalities |
| Mar 13, 1990 | EF4 | 72 km | 19.0 mi | 0 |
| Mar 29, 1981 | EF4 | 65 km | 5.1 mi | 0 |
| Aug 12, 1974 | EF4 | 82 km | 5.0 mi | 0 |
| Apr 11, 1965 | EF4 | 31 km | 91.5 mi | 1 |
| Apr 30, 1954 | EF4 | 95 km | 80.4 mi | 0 |
| Jun 1, 2007 | EF3 | 94 km | 15.8 mi | 0 |
| May 9, 1995 | EF3 | 51 km | 10.0 mi | 0 |
| Jun 19, 1993 | EF3 | 37 km | 14.0 mi | 0 |
| Jun 19, 1993 | EF3 | 89 km | 9.0 mi | 0 |
| Jul 13, 1992 | EF3 | 48 km | 5.0 mi | 0 |
| Mar 13, 1990 | EF3 | 52 km | 15.5 mi | 0 |
| May 8, 1988 | EF3 | 72 km | 16.0 mi | 0 |
| May 8, 1988 | EF3 | 31 km | 32.0 mi | 0 |
| Aug 5, 1979 | EF3 | 85 km | 5.7 mi | 0 |
| Aug 15, 1978 | EF3 | 82 km | 6.4 mi | 0 |
| Jun 20, 1974 | EF3 | 28 km | 10.6 mi | 1 |
| Jun 14, 1974 | EF3 | 69 km | 48.6 mi | 0 |
| May 13, 1974 | EF3 | 42 km | 3.6 mi | 0 |
| Jul 12, 1971 | EF3 | 82 km | 0.1 mi | 0 |
| Sep 9, 1970 | EF3 | 56 km | 4.7 mi | 0 |
Source: NOAA Storm Prediction Center (EF0+, 1950-2024, US only).
Monthly Weather
| Month | Avg Temperature | Precipitation | Summary |
|---|---|---|---|
| January | 19°F (-7°C) | 1.3 in | Coldest, Driest |
| February | 23°F (-5°C) | 1.7 in | |
| March | 36°F (2°C) | 2.2 in | |
| April | 48°F (9°C) | 3.4 in | |
| May | 60°F (15°C) | 4.2 in | |
| June | 70°F (21°C) | 5.1 in | Wettest |
| July | 73°F (23°C) | 4.2 in | Warmest |
| August | 71°F (21°C) | 4.2 in | |
| September | 63°F (17°C) | 3.6 in | |
| October | 51°F (10°C) | 2.9 in | |
| November | 37°F (3°C) | 2.1 in | |
| December | 25°F (-4°C) | 1.8 in |
Delmar has a seasonal temperature swing of 54°F / from 19°F in January to 73°F in July. Total annual precipitation is 36.7 inches, with June being the wettest month (5.1") and January the driest (1.3").