Mercer County Climate
Mercer County, Pennsylvania
NOAA NCEI 1991-2020 Climate NormalsAvg Annual Temp
48.5°F
Annual Precip
—
Annual Snowfall
—
Extreme Heat Days
6
days >= 90°F/yr
Monthly Temperature
Precipitation Calendar
Growing Season & Gardening
6a
Minimum winter temperature range for plant survival
2,525
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 cool, averaging 48.5°F annually, rare extreme heat with only 6 days above 90°F annually. This climate profile shapes everything from energy costs to outdoor recreation opportunities.
Seasonal Breakdown
Winters are cold, with January averaging 25.5°F. summers are pleasantly cool with July averaging 69.2°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 Pennsylvania statewide average temperature of 49.8°F.
Climate Profile
About Mercer County Weather
Cooler Temps in the Northwest
Mercer County averages 48.5°F, placing it well below the national median temperature. The climate is heavily influenced by its proximity to the Great Lakes, leading to cooler overall conditions.
Below the Pennsylvania Mean
The county sits 1.4 degrees below the state average of 49.9°F. Its location on the western border subjects it to colder air masses moving across the Midwestern plains.
Milder Summers Than Neighbors
With only 6 extreme heat days, Mercer offers a much cooler summer than Lawrence County’s 21 days. While local precipitation data is limited, its temperature patterns suggest a standard humid continental cycle.
Cold Winters and Gentle Summers
January averages a chilly 25.5°F, contributing to a 28.0°F winter average. Summer is mild by comparison, with July temperatures peaking at a comfortable 69.2°F.
Focus on Winter Heating Efficiency
Reliable heating is the priority given the cold 25.5°F January average. While specific snowfall records are limited, residents should prepare for typical Great Lakes winter conditions.
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.