Reference / Glossary / Practice and industry
Seasonality
Predictable variation in demand and media cost across the year. CPMs rise sharply in the fourth quarter as retail competition peaks, and category demand follows its own calendar. Automated bidding tools accept seasonality adjustments for short, known events.
Related terms
Used in The Signal
Cite this entry:
Agency Echelon. "Seasonality." Agency Echelon Reference, reviewed September 2026. https://agencyechelon.com/reference/glossary/seasonality/