Mercer County Climate
Mercer County, Missouri
Avg Annual Temp
51.1°F
Annual Precip
38.0"
Annual Snowfall
—
Extreme Heat Days
23.9
days >= 90°F/yr
Monthly Temperature
Precipitation Calendar
Seasonal Overview
National Comparison
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 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.