Mercer County Climate
Mercer County, New Jersey
Avg Annual Temp
53.5°F
Annual Precip
46.5"
Annual Snowfall
25.1"
Extreme Heat Days
23.9
days >= 90°F/yr
Monthly Temperature
Precipitation Calendar
Seasonal Overview
National Comparison
Climate Profile
About Mercer County Weather
Mirroring the typical American climate
Mercer County sits at an annual average of 53.5°F, almost exactly matching the national median. It represents a standard transition zone between northern and southern climate patterns.
The definition of New Jersey average
Mercer’s temperature is just 0.1 degrees shy of the New Jersey state average of 53.6°F. It serves as a benchmark for the state's overall climatic conditions.
Drier than the surrounding counties
The county receives only 46.5 inches of rain, significantly less than the 50.8 inches found in Hunterdon. This makes it one of the drier regions in the immediate area.
Hot summers with steady snowfall
July averages reach 75.6°F with 24 days of extreme heat annually. Winter brings 25.1 inches of snow, often falling when January temperatures hover around 31.5°F.
Adapt for moderate year-round extremes
A balanced heating and cooling plan is necessary to handle both the 24 heat days and the 25 inches of snow. Yard drainage is less of a concern here than in wetter neighboring counties.
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.