Seasonality: plan the budget, not the panic

Every seasonal business runs the same annual cycle: demand rises, costs rise faster, budgets are exhausted mid-month, and everyone reacts to a pattern that was entirely predictable.

Most of it is avoidable with two mechanisms that already exist in the account.

What smart bidding does on its own

It adapts to changing conversion rates, but it learns from recent history — so it discovers your peak after your peak has started. During the transition it is bidding on last month's assumptions, which means underbidding into a rising market.

The same applies in reverse at the end of a season, where it overbids into falling demand.

Seasonality adjustments

For short, sharp, predictable changes — a sale weekend, a holiday period, a known promotion — you can tell Google in advance that conversion rate will change, and by how much.

The constraints matter: intended for periods of roughly one to seven days, and for changes you can actually quantify. Used for long periods or vague expectations it does more harm than good.

The value is that bidding adjusts on day one rather than day four, which on a three-day sale is the difference between working and not.

Data exclusions

The counterpart. When something breaks — the tag was down, the site was offline, tracking was broken for two days — exclude that period so bidding does not learn from data reflecting an outage rather than the market.

This is the more commonly needed of the two and the more commonly forgotten. Every account has had a broken measurement period, and every one of those periods is currently teaching the bidding algorithm something false.

Budget planning that actually helps

Take last year's spend and conversions by week. Where did the budget cap bind? Where did cost per acquisition rise, and by how much?

That gives a defensible plan: which weeks need more budget, and what return to expect at that higher spend. It is a considerably better conversation than "we need more budget" in the middle of a peak.

The unglamorous point

Almost everything about seasonality is knowable in advance from your own history. The reason it feels like an emergency every year is that nobody looked at last year's numbers before it started.