Glossary
What is a seasonality adjustment in Google Ads?
Melvin Salas1 min readVerified 4 October 2026
Short answer
A seasonality adjustment is, in Google's words, an advanced tool that can be used to inform Smart Bidding of expected changes in conversion rates for future events like promotions or sales. You schedule a conversion rate adjustment, an increase or a decrease, for the event's dates, and Google says your campaigns return to their pre-adjusted performance after the event is finished.
Google says to use seasonality adjustments only if you expect major changes to conversion rates, because Smart Bidding already manages seasonal events. It describes them as ideal for short events of 1 to 7 days, and says they may not work as well if you use them for extended periods (more than 14 days at a time).
Google says they are currently available for Search, Shopping and display campaigns using target ROAS and target CPA bid strategies, as well as Performance Max and App (beta) campaigns using all bid strategies, and that they aren't supported in Travel campaigns. Its example: if you're expecting conversion rates to increase by 50% during a three-day sale, you can create an adjustment that increases the conversion rate by up to 50% for those three days, and no negative adjustment is needed when the promotion is over.
Our reading, not Google's: an adjustment is a forecast you hand the bidder, not a measurement of anything. It belongs to a short event you know is coming. It is not a way to explain a month that has already happened, and a good month is worth explaining before anyone schedules one for next year.
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