New Castle County Climate
New Castle County, Delaware
Avg Annual Temp
54.9°F
Annual Precip
47.5"
Annual Snowfall
16.1"
Extreme Heat Days
24.100000000000005
days >= 90°F/yr
Monthly Temperature
Precipitation Calendar
Seasonal Overview
National Comparison
Climate Profile
About New Castle County Weather
Matching the national temperature median
At 54.9°F annually, New Castle County aligns closely with the national median temperature for U.S. counties. It offers a balanced four-season climate that avoids the extreme heat found further south.
Delaware’s coolest county
New Castle is Delaware’s coolest county, falling 1.5 degrees below the state average of 56.4°F. While the rest of the state leans warmer, this northern corridor maintains a more temperate profile year-round.
Chillier than southern neighbors
The county is significantly cooler than its southern neighbor Kent, which averages 57.1°F. It also receives 16.1 inches of snow, the highest volume in Delaware, distinguishing it from the sandier coastal regions.
The state's snowiest winters
Winter brings a chilly January average of 32.7°F, contributing to the state's most robust snowfall totals. Summers remain warm with 24 days over 90°F, though the July average of 76.9°F is the lowest in the state.
Prepare for freezing temperatures
Reliable heating and insulation are vital as winter temperatures frequently dip below freezing. Residents should also invest in snow shovels or blowers to manage the county's 16.1-inch annual snow accumulation.
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.