Should You Turn Off Seasonality Adjustments for Black Friday Google Ads?

No — leave Google Ads seasonality bid adjustments off for Black Friday and Cyber Monday. Optmyzr's study of more than 5,000 Google Ads accounts found that advertisers who left seasonality adjustments off during BFCM and let Smart Bidding handle the surge performed better than those who applied manual adjustments, and a separate BrandIQ analysis of 2022-2024 data found manual adjusters saw CPC inflation run nearly double that of accounts without them.

What a Seasonality Adjustment Actually Does

A seasonality adjustment tells Google's Smart Bidding to expect a conversion rate change over a set date range, overriding what the algorithm would otherwise forecast on its own from historical data. It's designed for events the system has no other way to anticipate.

Why It Backfires on Widely-Recognized Holidays

Google's Smart Bidding already incorporates historical seasonal patterns for well-known shopping events, since so much aggregate advertiser data trains the system on exactly this pattern every year. Layering a manual adjustment on top double-counts the expected lift, pushing bids higher than the auction actually calls for.

• Optmyzr's recommendation: leave the adjustment off specifically for Black Friday, Cyber Monday, Christmas, and other widely recognized holidays.
• BrandIQ's 2022-2024 finding: manual seasonality adjusters saw CPC inflation run nearly double that of advertisers who didn't apply one over the same BFCM period.

When a Seasonality Adjustment Still Makes Sense

Optmyzr's broader guidance reserves seasonality adjustments for events the algorithm has no way to already know about — a company-specific sale, a one-off promotion, or a regional event without enough aggregate search history behind it. Black Friday and Cyber Monday are the opposite case: they're already baked into Smart Bidding's pattern recognition across the entire advertiser base, so an added manual override just distorts the auction input.

If You Already Set an Adjustment for This Season

Check your account's Seasonality adjustments panel now rather than waiting for Black Friday week to arrive. An adjustment set months ago for a different promotion can still be active and overlapping with BFCM dates without you noticing, which recreates the exact double-counting problem both studies flag — remove or shorten any adjustment whose date range runs into November 27 through 30 unless it's covering something the algorithm genuinely can't already see, like a one-time discount code campaign unrelated to the holiday itself.

What to Do Instead

• Raise budgets, not bid-strategy overrides, so Smart Bidding has room to spend into the demand spike it already expects.
• Tighten conversion tracking before the week starts, since Smart Bidding's seasonal pattern recognition is only as good as the conversion data feeding it.
• Monitor daily rather than set-and-forget, since even without a manual adjustment you still want to catch budget caps or disapprovals mid-week.
• Audit existing adjustments for date overlap, since a leftover adjustment from an earlier campaign can quietly double-count the same seasonal lift Smart Bidding already forecasts.

Bottom Line

Skip the manual seasonality adjustment for Black Friday and Cyber Monday 2026 specifically. Smart Bidding already expects the surge, and two independent analyses found that overriding it with a manual adjustment increased costs rather than improving performance. Save seasonality adjustments for promotions the algorithm genuinely couldn't see coming.

Source: Optmyzr, analysis of 5,000+ Google Ads accounts on seasonality adjustments, via Search Engine Land; BrandIQ, 2022-2024 Black Friday/Cyber Monday CPC analysis.