Delaware County Climate
Delaware County, Iowa
Avg Annual Temp
46.3°F
Annual Precip
38.6"
Annual Snowfall
34.7"
Extreme Heat Days
9.2
days >= 90°F/yr
Monthly Temperature
Precipitation Calendar
Seasonal Overview
National Comparison
Climate Profile
About Delaware County Weather
A Cooler Midwestern Stronghold
Delaware County’s 46.3°F annual average is notably cooler than the national median, reflecting its northern latitude. The county receives a healthy 38.6 inches of precipitation, making it wetter than many parts of the Great Plains. This climate is characterized by long, snowy winters and mild, comfortable summers.
Below the Iowa Temperature Average
Delaware County's average temp of 46.3°F falls below the state average of 48.0°F. However, it receives more precipitation than the average Iowa county, logging 38.6 inches versus the state’s 36.1. This creates a landscape that is both cooler and moisture-rich compared to the rest of the state.
Colder Than Its River Neighbors
Compared to nearby Dubuque County, Delaware is slightly cooler, with an average of 46.3°F vs 47.8°F. It is significantly more temperate than northwestern Emmet County, which bottoms out at 44.7°F. Delaware strikes a balance, offering more snow but less extreme winter cold than the far northern border.
Mild Summers and Heavy Snowfall
Summers are remarkably pleasant, with only 9 days per year hitting 90°F and an average July temperature of 71.6°F. The trade-off is a heavy winter, bringing 34.7 inches of annual snowfall and a January average of 17.1°F. This county is a haven for those who prefer cool summers over intense heat.
Prioritize Winter Readiness
Winter gear is the top priority here, as residents must navigate nearly 35 inches of snow and sub-20-degree January averages. While summer cooling needs are lower than in southern Iowa, high-performance heating is a must for the three-month winter average of 20.7°F. Outdoor enthusiasts should plan for a long snow season and a brief, mild window for summer activities.
Frequently Asked Questions
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Data source: NOAA National Centers for Environmental Information (NCEI), U.S. Climate Normals 1991-2020.
Climate normals are 30-year averages of weather variables computed from 1991 to 2020. Station data is aggregated to county level using spatial averaging. Data is informational only — not a substitute for official National Weather Service forecasts or emergency weather warnings.