Williamson County Climate
Williamson County, Texas
Avg Annual Temp
67.3°F
Annual Precip
35.9"
Annual Snowfall
0.0"
Extreme Heat Days
112.56666666666666
days >= 90°F/yr
Monthly Temperature
Precipitation Calendar
Seasonal Overview
National Comparison
Climate Profile
About Williamson County Weather
Warmer than most of the nation
Williamson County maintains an annual average temperature of 67.3°F, significantly higher than the national median. This humid subtropical climate sees nearly 36 inches of rainfall each year, keeping the landscape greener than its western neighbors.
Exceeding the Texas average
The county's average temperature sits nearly two degrees above the Texas state average of 65.5°F. While not the hottest in the state, it ranks among the warmer central regions, driven by intense summer heat.
A central Texas climate hub
Williamson County shares a similar profile with neighboring Travis County but experiences slightly more rain than counties further west. Its 35.9 inches of annual precipitation is four inches higher than the state average.
Long summers and mild winters
The county endures 113 extreme heat days annually where temperatures top 90°F. Winters are manageable with a January average of 48.8°F and effectively zero annual snowfall.
Prepare for the heat dome
Residents should prioritize high-efficiency HVAC systems to handle three months of summer highs averaging over 83°F. Outdoor activities are best scheduled for the mild 50.6°F winter window.
Frequently Asked Questions
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Data source: NOAA National Centers for Environmental Information (NCEI), U.S. Climate Normals 1991-2020.
Climate normals are 30-year averages of weather variables computed from 1991 to 2020. Station data is aggregated to county level using spatial averaging. Data is informational only — not a substitute for official National Weather Service forecasts or emergency weather warnings.