Mercer County Climate
Mercer County, Missouri
NOAA NCEI 1991-2020 Climate NormalsAvg Annual Temp
51.1°F
Annual Precip
38.0"
Annual Snowfall
—
Extreme Heat Days
24
days >= 90°F/yr
Monthly Temperature
Precipitation Calendar
Growing Season & Gardening
5b
Minimum winter temperature range for plant survival
3,378
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 51.1°F, moderate rainfall of 38.0 inches per year, occasional hot days — 23.9 per year above 90°F. This climate profile shapes everything from energy costs to outdoor recreation opportunities.
Seasonal Breakdown
Winters are very cold — January averages 24.2°F. summers are warm — July averages 75.6°F. Residents experience a substantial 51°F difference between winter and summer.
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 is 3.8°F cooler than the Missouri statewide average of 54.9°F, it is also noticeably drier, receiving 5.7 inches less precipitation than the state average.
Climate Profile
About Mercer County Weather
Cooler Northern Missouri Profile
Mercer County's annual average temperature of 51.1°F is lower than the national median, reflecting its northern latitude. It receives 38 inches of precipitation, which is drier than many other parts of the Midwest. This climate is characterized by shorter summers and longer, more distinct winters.
Well Below State Average
At 51.1°F, Mercer is nearly four degrees cooler than the Missouri state average of 54.9°F. It is one of the coolest counties in the state, contrasting sharply with southern Missouri. The January average of 24.2°F highlights its position as a northern state outlier.
Coolest in the Region
Mercer County is roughly two degrees cooler on average than Marion County to its east. It records only 24 days of extreme heat, fewer than any other county in this local comparison. This makes it a regional leader in cool-weather patterns and winter longevity.
Sharp Winters and Moderate Summers
Winters are cold with a January average of 24.2°F and a winter seasonal average of 27.3°F. While specific snowfall data is unavailable, the cold temperatures ensure frequent freezes. Summers are mild by Missouri standards, with a July average of 75.6°F.
Focus on Winter Heating
Heating systems must be highly reliable to handle the prolonged winter average of 27.3°F. With 38 inches of annual precipitation, the region is drier than the state average, but ice management remains a concern. Home insulation should be a primary focus for all residents.
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.