Johnson County Climate
Johnson County, Indiana
NOAA NCEI 1991-2020 Climate NormalsAvg Annual Temp
51.6°F
Annual Precip
45.4"
Annual Snowfall
16.9"
Extreme Heat Days
18
days >= 90°F/yr
Monthly Temperature
Precipitation Calendar
Growing Season & Gardening
6a
Minimum winter temperature range for plant survival
3,303
Supports most vegetables & fruits
Seasonal Overview
National Comparison
7-Day Outlook
Forecast
Current Conditions
Air Quality
Safety
Weather Alerts
Climate Advisory: Johnson County
Climate Verdict
Johnson County has a mild, with an average annual temperature of 51.6°F, moderately wet with 45.4 inches of annual precipitation, rare extreme heat with only 17.7 days above 90°F annually, light snow averaging 16.9 inches per year. This climate profile shapes everything from energy costs to outdoor recreation opportunities.
Seasonal Breakdown
Winters are cold, with January averaging 26.6°F. summers are warm — July averages 74.0°F. The 47°F seasonal variation provides noticeable but manageable change.
Outdoor & Gardening Guidance
Growing season and gardening data is currently limited for Johnson County. Check the USDA Plant Hardiness Zone Map and local extension office for specific guidance.
Regional Context
Johnson County closely matches the Indiana statewide average temperature of 52.4°F.
Climate Profile
About Johnson County Weather
Central Indiana's Continental Climate
Johnson County tracks an annual average of 51.6°F, which is slightly cooler than the national median. It experiences the classic humid continental climate of the central United States.
Reflecting the State Temperature Benchmark
The county sits just below the Indiana state average of 52.2°F. Its central location makes it a benchmark for the state's typical weather patterns.
Predictable Weather for the Metro Area
Its climate closely matches that of Marion and Shelby counties in the Indianapolis metro area. Precipitation levels of 45.4 inches are slightly above the state average of 43.9 inches.
Balanced Seasons with Moderate Snow
Summers feature 18 days of extreme heat and a July peak of 74.0°F. Winter brings 16.9 inches of snow and an average temperature of 29.4°F during the coldest months.
Prepare for a Balanced Climate
A dual-season HVAC approach is best for the 18 heat days and freezing winter nights. Residents should prepare for moderate snow accumulation that typically clears within a few days.
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.