Union County Climate
Union County, Iowa
NOAA NCEI 1991-2020 Climate NormalsAvg Annual Temp
48.8°F
Annual Precip
37.5"
Annual Snowfall
27.7"
Extreme Heat Days
18
days >= 90°F/yr
Monthly Temperature
Precipitation Calendar
Growing Season & Gardening
5b
Minimum winter temperature range for plant survival
3,075
Supports most vegetables & fruits
Seasonal Overview
National Comparison
7-Day Outlook
Forecast
Current Conditions
Air Quality
Safety
Weather Alerts
Climate Advisory: Union County
Climate Verdict
Union County has a cool, averaging 48.8°F annually, moderate rainfall of 37.5 inches per year, rare extreme heat with only 18.3 days above 90°F annually, moderate snowfall of 27.7 inches annually. This climate profile shapes everything from energy costs to outdoor recreation opportunities.
Seasonal Breakdown
Winters are very cold — January averages 20.5°F. summers are warm — July averages 74.0°F. Residents experience a substantial 54°F difference between winter and summer.
Outdoor & Gardening Guidance
Growing season and gardening data is currently limited for Union County. Check the USDA Plant Hardiness Zone Map and local extension office for specific guidance.
Regional Context
Union County closely matches the Iowa statewide average temperature of 48.0°F.
Climate Profile
About Union County Weather
Union County Sees Moderate Continental Weather
Union County's annual average temperature of 48.8°F reflects a temperate version of the continental climate. It stays cooler than the national median but avoids the most extreme cold found further north.
Slightly Warmer Than the Iowa Average
The county's average of 48.8°F is 0.8 degrees warmer than the Iowa state average. This makes it a moderately warm entry in the state's southern half.
Ample Precipitation for the Region
Union County receives 37.5 inches of precipitation annually, which is about 1.4 inches more than the state average. This consistent rainfall supports the local agricultural economy and natural greenery.
Hot Summers and Balanced Snowfall
The area experiences 18 days of extreme heat over 90°F with a July average of 74.0°F. Winters are manageable but cold, averaging 27.7 inches of annual snowfall.
Prepare for Heat and Rainfall
Residents should plan for 18 days of intense summer heat and higher-than-average precipitation. Keeping gutters clear and HVAC systems serviced will help manage the humid, rainy summers.
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.