Mercer County Climate
Mercer County, Ohio
NOAA NCEI 1991-2020 Climate NormalsAvg Annual Temp
51.4°F
Annual Precip
38.9"
Annual Snowfall
28.8"
Extreme Heat Days
12
days >= 90°F/yr
Monthly Temperature
Precipitation Calendar
Growing Season & Gardening
6a
Minimum winter temperature range for plant survival
3,272
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 51.4°F, moderate rainfall of 38.9 inches per year, rare extreme heat with only 11.7 days above 90°F annually, moderate snowfall of 28.8 inches annually. This climate profile shapes everything from energy costs to outdoor recreation opportunities.
Seasonal Breakdown
Winters are cold, with January averaging 26.2°F. summers are warm — July averages 73.4°F. The 47°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 Ohio statewide average temperature of 51.5°F, it is somewhat drier than average for Ohio.
Climate Profile
About Mercer County Weather
Standard Midwestern Climate Trends
Mercer County records an annual average temperature of 51.4°F, placing it right in line with the national median. This provides a balanced climate typical of the American interior.
Reflecting the Ohio Average
With an average temperature nearly identical to the state's 51.5°F, Mercer serves as a climatic benchmark for Ohio. It avoids the extremes found in the lake-effect north or the humid south.
Drier Fields in Western Ohio
The county sees 38.9 inches of annual precipitation, which is lower than the Ohio average of 41.2 inches. This drier profile distinguishes Mercer from its eastern neighbors that face heavier rainfall.
Consistent Snow and Warm Summers
Mercer faces 28.8 inches of annual snowfall and a chilly January average of 26.2°F. Summer brings a July average of 73.4°F and 12 days where the thermometer hits 90°F or higher.
Balanced Seasonal Preparation Required
Residents should invest in both reliable snow tires for the 28.8 inches of snow and efficient cooling for the 12 extreme heat days. Managing the 38.9 inches of rain is generally straightforward compared to wetter state regions.
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.