Mercer County Climate
Mercer County, New Jersey
NOAA NCEI 1991-2020 Climate NormalsAvg Annual Temp
53.5°F
Annual Precip
46.5"
Annual Snowfall
25.1"
Extreme Heat Days
24
days >= 90°F/yr
Monthly Temperature
Precipitation Calendar
Growing Season & Gardening
7a
Minimum winter temperature range for plant survival
3,411
Supports most vegetables & fruits
Seasonal Overview
National Comparison
7-Day Outlook
Forecast
Current Conditions
Air Quality
Safety
Weather Alerts
Climate Advisory: Mercer County
Climate Verdict
Mercer County has a mild, with an average annual temperature of 53.5°F, moderately wet with 46.5 inches of annual precipitation, occasional hot days — 23.9 per year above 90°F, moderate snowfall of 25.1 inches annually. This climate profile shapes everything from energy costs to outdoor recreation opportunities.
Seasonal Breakdown
Winters are cold, with January averaging 31.5°F. summers are warm — July averages 75.6°F. The 44°F seasonal variation provides noticeable but manageable change.
Outdoor & Gardening Guidance
Growing season and gardening data is currently limited for Mercer County. Check the USDA Plant Hardiness Zone Map and local extension office for specific guidance.
Regional Context
Mercer County closely matches the New Jersey statewide average temperature of 53.6°F.
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 sources: NOAA National Centers for Environmental Information (NCEI), U.S. Climate Normals 1991-2020. Forecast and alert data from National Weather Service API. Air quality data from Open-Meteo.
Climate normals are 30-year averages of weather variables. Station data is aggregated to county level. Forecasts and alerts are fetched live and may change frequently. Data is informational only — not a substitute for official National Weather Service forecasts or emergency weather warnings.