Glenn County Climate
Glenn County, California
Avg Annual Temp
62.0°F
Annual Precip
21.5"
Annual Snowfall
0.0"
Extreme Heat Days
95.46666666666664
days >= 90°F/yr
Monthly Temperature
Precipitation Calendar
Seasonal Overview
National Comparison
Climate Profile
About Glenn County Weather
Warm Interior Mediterranean Climate
Glenn County’s annual average of 62.0°F is significantly higher than the national median temperature. This interior region sees 21.5 inches of rain, placing it in a dry Mediterranean climate zone.
Warmer Than the State Average
Averaging 62.0°F, Glenn is warmer than the California state average of 58.7°F. It sits among the warmer tier of Sacramento Valley counties where heat accumulates away from the coast.
Mirroring the Northern Valley
Its climate closely mirrors neighboring Butte and Colusa counties, which are characterized by hot, dry summers. With 95 extreme heat days, it faces a thermal profile nearly identical to its agricultural neighbors.
Intense Summers and Snowless Winters
Summers are intense with an average of 76.6°F, while winters remain mild at 48.0°F. The county records zero inches of annual snowfall, emphasizing the dominance of the valley's warm air masses.
Manage the High-Heat Days
Homeowners should invest in high-capacity HVAC systems to combat nearly 100 days of temperatures over 90°F. Lightweight summer clothing is essential, while heavy winter gear is rarely necessary given the mild 47.1°F January average.
Frequently Asked Questions
What is the average temperature in Glenn County?
How much rain does Glenn County get?
Does it snow in Glenn County?
How hot does Glenn County get in summer?
How cold are winters in Glenn County?
Track your own weather in Glenn County
Ambient Weather personal weather stations give you hyperlocal climate data.
Sponsored
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.