Glossary
What is Ad seasonality (Q4)?
Also called: seasonality, Q4 CPMs, Q1 CPM drop
Ad seasonality is the yearly rise and fall in advertiser demand: CPMs usually climb through Q4's holiday season and drop in January.
हिंदी में पढ़ेंAds are sold in auctions, so prices follow demand. In November and December, retailers bid hard for holiday shoppers during Q4, October to December. In January, many advertisers start new budgets and spend slowly. Fewer bids mean lower CPMs and a lower page RPM, even when nothing on your site has changed.
One industry dataset from DataBeat, as reported by PPC Land, showed US programmatic CPMs down 32.5% from December 2025 to January 2026, but up 23.6% on January 2025. That is the test: compare January with last January, not with December. If revenue is up year on year, the drop is probably the season, not a penalty. Check Policy center anyway.
Floors should follow the season. A floor that lifts prices in Q4 can leave January impressions unsold, so review floors when the season turns, or use dynamic floors that follow real bid data.
Example
A site's page RPM is $4.00 in December and $2.60 in January, down 35%. Last January it was $2.40, so year on year it is up about 8% ($2.60 ÷ $2.40 ≈ 1.083). That points to the season, not a problem.
Why it matters to publishers
Reading a January dip as a penalty leads to panicked changes that cost money. Year-on-year comparisons and seasonal floors keep decisions grounded.