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Seasonal Air Quality Patterns

Understand how air quality changes throughout the year. Discover seasonal patterns, regional differences, and optimal times for outdoor activities across major US cities.

Air Quality by Season

Specialized Seasonal Topics

Planning & Relocation Guides

Key Seasonal Patterns

Best Air Quality Months

  • October-November: Post-summer, pre-winter inversion
  • March-April: Spring transitions with lower ozone
  • Early December: Before winter heating season peaks

Worst Air Quality Months

  • July-August: Peak ozone season and wildfire smoke
  • January-February: Winter inversions trap pollution
  • September: Extended wildfire season in Western states

Regional Seasonal Differences

West Coast

Summer wildfire season dominates air quality patterns. Best months: October-May.

Mountain West

Winter inversions in valleys create pollution traps. Best months: June-September.

East Coast

Summer ozone and humidity. Most consistent year-round air quality.