Umatilla County Climate
Umatilla County, Oregon
NOAA NCEI 1991-2020 Climate NormalsAvg Annual Temp
51.9°F
Annual Precip
15.2"
Annual Snowfall
29.8"
Extreme Heat Days
38
days >= 90°F/yr
Monthly Temperature
Precipitation Calendar
Growing Season & Gardening
7a
Minimum winter temperature range for plant survival
2,693
Supports most vegetables & fruits
Seasonal Overview
National Comparison
7-Day Outlook
Forecast
Current Conditions
Air Quality
Safety
Weather Alerts
Climate Advisory: Umatilla County
Climate Verdict
Umatilla County has a mild, with an average annual temperature of 51.9°F, semi-arid conditions with only 15.2 inches of annual precipitation, occasional hot days — 38.02 per year above 90°F, moderate snowfall of 29.8 inches annually. This climate profile shapes everything from energy costs to outdoor recreation opportunities.
Seasonal Breakdown
Winters are cold, with January averaging 34.8°F. summers are warm — July averages 72.2°F. The 37°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 Umatilla County. Check the USDA Plant Hardiness Zone Map and local extension office for specific guidance.
Regional Context
Umatilla County closely matches the Oregon statewide average temperature of 50.5°F, it is also noticeably drier, receiving 22.2 inches less precipitation than the state average.
Climate Profile
About Umatilla County Weather
A Typical But Dry National Profile
Umatilla County’s 51.9°F average temperature aligns closely with the national median. However, it is much drier than the U.S. average, receiving only 15.2 inches of precipitation.
Warmer and Snowier than the Average
At 51.9°F, the county is warmer than the Oregon state average of 50.5°F. It also receives 29.8 inches of snow, which is quite high compared to the rain-heavy western half of the state.
The Snowy Side of the Plateau
Umatilla is similar in temperature to Morrow County but receives nearly triple the snowfall. It averages 29.8 inches of snow compared to Morrow's 8.3 inches.
Intense Heat and Significant Snowfall
The county experiences 38 days of extreme heat above 90°F, one of the highest counts in the state. Winters bring a January average of 34.8°F and substantial snow accumulations.
Invest in Cooling and Clearing
Residents need high-efficiency cooling to manage over five weeks of extreme summer heat. A reliable snow blower or shovel is also essential for managing nearly 30 inches of winter snow.
Frequently Asked Questions
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Track your own weather in Umatilla 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.