Ada County Climate
Ada County, Idaho
NOAA NCEI 1991-2020 Climate NormalsAvg Annual Temp
52.8°F
Annual Precip
13.1"
Annual Snowfall
37.5"
Extreme Heat Days
53
days >= 90°F/yr
Monthly Temperature
Precipitation Calendar
Growing Season & Gardening
7a
Minimum winter temperature range for plant survival
3,173
Supports most vegetables & fruits
Seasonal Overview
National Comparison
7-Day Outlook
Forecast
Current Conditions
Air Quality
Safety
Weather Alerts
Climate Advisory: Ada County
Climate Verdict
Ada County has a mild, with an average annual temperature of 52.8°F, arid conditions receiving just 13.1 inches of precipitation annually, occasional hot days — 53.35 per year above 90°F, moderate snowfall of 37.5 inches annually. This climate profile shapes everything from energy costs to outdoor recreation opportunities.
Seasonal Breakdown
Winters are cold, with January averaging 32.3°F. summers are warm — July averages 76.4°F. The 44°F seasonal variation provides noticeable but manageable change. December is typically the coldest month and July the warmest.
Outdoor & Gardening Guidance
Growing season and gardening data is currently limited for Ada County. Check the USDA Plant Hardiness Zone Map and local extension office for specific guidance.
Regional Context
Ada County is 6.2°F warmer than the Idaho statewide average of 46.5°F, it is somewhat drier than average for Idaho, the county experiences 23.155015817515814 more extreme heat days than the state average.
Climate Profile
About Ada County Weather
Ada County matches national temperature averages
The county's average annual temperature of 52.8°F aligns almost perfectly with the national median. This creates a semi-arid climate that balances high-desert warmth with distinct seasonal shifts.
Idaho's warmest pocket of activity
Ada County is significantly warmer than the Idaho average of 46.5°F, making it one of the state's mildest regions. This warmth supports the capital's growth but brings more intense summer heat than most of the state.
Warmer and drier than mountain neighbors
With only 13.1 inches of annual precipitation, Ada is much drier than neighboring Boise County. It averages nearly 8 degrees warmer than its northern neighbors, serving as the Treasure Valley's heat center.
Hot summers and manageable winters
Residents face 53 days of extreme heat above 90°F, far exceeding the state norm. Winters remain relatively mild with an average January temperature of 32.3°F and a modest 37.5 inches of snowfall.
Prioritize cooling and summer hydration
Investing in high-efficiency HVAC systems is essential to handle the two months of frequent 90-degree days. Water-wise landscaping helps residents maintain properties during the dry 13.1-inch annual rainfall cycle.
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.