Washington County Climate
Washington County, Idaho
NOAA NCEI 1991-2020 Climate NormalsAvg Annual Temp
51.9°F
Annual Precip
16.6"
Annual Snowfall
—
Extreme Heat Days
63
days >= 90°F/yr
Monthly Temperature
Precipitation Calendar
Growing Season & Gardening
7a
Minimum winter temperature range for plant survival
3,184
Supports most vegetables & fruits
Seasonal Overview
National Comparison
7-Day Outlook
Forecast
Current Conditions
Air Quality
Safety
Weather Alerts
Climate Advisory: Washington County
Climate Verdict
Washington County has a mild, with an average annual temperature of 51.9°F, semi-arid conditions with only 16.6 inches of annual precipitation, significant summer heat with 63.1 days annually above 90°F. This climate profile shapes everything from energy costs to outdoor recreation opportunities.
Seasonal Breakdown
Winters are cold, with January averaging 28.7°F. summers are warm — July averages 77.2°F. The 49°F seasonal variation provides noticeable but manageable change.
Outdoor & Gardening Guidance
Growing season and gardening data is currently limited for Washington County. Check the USDA Plant Hardiness Zone Map and local extension office for specific guidance.
Regional Context
Washington County is 5.3°F warmer than the Idaho statewide average of 46.5°F, the county experiences 32.90501581751582 more extreme heat days than the state average.
Climate Profile
About Washington County Weather
Warmest of the Region
Washington County averages 51.9°F annually, coming within two degrees of the national median. This makes it one of the more temperate climates in the Pacific Northwest interior.
Leading Idaho in Temperature
At 51.9°F, Washington County is significantly warmer than the Idaho state average of 46.5°F. It ranks as one of the warmest counties in the state.
Consistent State Rainfall Patterns
The county sees 16.6 inches of precipitation, almost matching the Idaho average of 17.0 inches. It is much drier than the mountainous counties to its immediate east.
Intense Summer Heat Waves
Summers are very hot, featuring 63 days per year with temperatures at or above 90°F. Winters are moderate for the state, averaging 30.8°F between December and February.
Cooling is the Priority
Residents must maintain robust HVAC systems to handle two full months of extreme summer heat. While snowfall data is limited, the focus remains on summer cooling and water management.
Frequently Asked Questions
What is the average temperature in Washington County?
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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.