How can I tell if seasonality caused my performance drop?

Seasonality vs. “Something Broke”: the fastest way to tell what really caused the drop

Start by identifying which part of the funnel fell first

When seasonality is the main driver, the earliest signal is usually a change in demand: impressions fall because fewer people are searching (or fewer people are shopping with intent). When an account issue is the driver, you’ll often see demand remain available, but your ability to capture it weakens (for example, impression share drops due to rank or budget) or your post-click performance collapses (for example, conversion rate drops while traffic stays steady).

In practical terms, seasonality typically shows up as a performance shift that’s “market-shaped,” not “account-shaped.” Market-shaped shifts tend to affect multiple campaigns at once, often across similar themes, and they frequently repeat on a predictable calendar (back-to-school, tax season, winter slowdowns, summer lulls, holiday peaks). Account-shaped shifts often trace back to a specific change: bidding, budgets, targeting, tracking, ads/landing pages, or policy-related eligibility.

Use this quick diagnostic sequence before you call it seasonality

• Step 1: Compare the same date range year-over-year (and also compare week-over-week) to see if the pattern repeats.
• Step 2: Check whether the decline starts at impressions (demand drop), impression share (you lost auctions), or conversion rate (site/offer/intent mismatch).
• Step 3: Review automated “why did this change?” diagnostics (Explanations) on the campaigns/ad groups that dropped most.
• Step 4: Confirm there were no meaningful account edits around the inflection point (Change history).

If Steps 2–4 point to lost eligibility (budget, rank, disapprovals, targeting restrictions, bidding learning resets, or tracking outages), treat it as an account problem first. Seasonality can still be present, but it’s rarely the only culprit when you can clearly see lost impression share, abrupt conversion tracking anomalies, or a major settings change.

How to prove seasonality inside Google Ads (with specific signals to look for)

1) Demand signals: impressions and clicks fall, but auction capture looks stable

The cleanest seasonality story looks like this: impressions and clicks trend down, but your ability to win auctions is not suddenly worse. In other words, your impression share doesn’t collapse; there’s simply less total opportunity available. If you see impressions down while impression share is flat (or even slightly up), that’s a strong indicator demand softened and you’re not being “pushed out” of the market.

To validate this, pull a date comparison and segment it by campaign, network, device, and geography. True seasonality often concentrates in specific product lines, locations, or device mixes (for example, mobile-only dips during certain periods, or regional weather-driven behavior). If the decline is isolated to one campaign while everything else is stable, seasonality is less likely than a campaign-level issue.

2) Auction signals: the market didn’t shrink—competition intensified

Seasonality doesn’t always mean “less demand.” In many categories, peak season produces higher CPCs and lower efficiency because competitors flood the auction. This version of seasonality shows up as more competition, not necessarily fewer searches.

This is where you use two core reports. First, look at impression share and the two “lost” metrics that explain why your ads didn’t show: lost due to budget and lost due to rank. If lost due to budget rises, you’re simply capped while demand (and auction volume) is available; if lost due to rank rises, competitors are beating you on Ad Rank (which can be bids, quality, or both). Second, review Auction insights to see whether overlap and “position above” pressure increased during the period you dropped. In peak seasons, it’s common to see the same competitors show more often, show above you more frequently, and take a larger share of top-of-page visibility.

3) Conversion-rate signals: traffic quality shifts even when volume doesn’t

Some seasonal drops happen because intent changes, not because search volume disappears. For example, in research-heavy periods, you may keep getting clicks, but people are browsing, comparing, and delaying purchase. That typically shows up as a conversion rate decline, longer conversion lag, or a shift in which search terms and audiences are driving spend.

Before you blame seasonality, isolate whether the conversion rate decline is broad (affecting many campaigns similarly) or concentrated (one landing page, one product set, one device). A broad shift that aligns with the calendar is consistent with seasonality. A concentrated shift that aligns with a site release, checkout change, pricing change, or tracking change is usually not seasonality.

4) Use in-platform insight tools to confirm the market trend (not just your account trend)

The Insights area is designed to show market movement, including search trends and predicted demand. When these features are available in your account, they’re especially useful for seasonality questions because they help you separate “people searched less” from “we performed worse.” Look for trend summaries that plot search interest alongside your results, and review predicted trends/demand forecasts to see whether the category is expected to rise or fall around the dates you’re analyzing. If the market interest line drops in the same period your impressions drop, that’s strong corroboration of seasonality.

Also, don’t ignore the simplest explanation tool: Explanations. When you compare two date ranges and see a large fluctuation, Explanations can surface common causes like bidding changes, budget limits, competition shifts, or conversion-rate changes. It’s not perfect, but it’s a fast way to avoid spending hours on analysis when the platform already detected the main driver.

How to respond once you confirm it’s seasonality (and protect results year-round)

Adjust expectations first: seasonality is not always “fixable,” but it is manageable

If demand truly fell, your best “fix” might simply be adapting your KPIs and pacing. I’ve managed accounts where the smartest move in the seasonal trough was to prioritize efficiency, maintain coverage on the highest-intent queries, and preserve remarketing/audience signal quality—so the account is positioned to scale aggressively when demand returns.

If competition surged (peak season), you typically manage the tradeoff between volume and efficiency: either pay more to maintain volume, or accept less volume to protect CPA/ROAS. The key is making that decision intentionally and early, not after two weeks of chasing yesterday’s performance.

Use forecasting and planning to avoid overreacting inside the auction

Planning tools can help you model budget and outcome tradeoffs and are refreshed frequently, with forecasts built using very recent performance signals and adjusted for seasonality. For accounts that face rapid market swings, shorter planning cycles (weekly) tend to produce more realistic pacing decisions than monthly plans.

As you go into known seasonal periods, build a simple internal calendar of the handful of weeks that always behave differently for your business, then map budget flexibility and target flexibility to those periods. Most advertisers lose performance in peak seasons because they refuse to loosen constraints (budget caps, overly aggressive ROAS targets, or tight CPA targets) while the auction becomes more expensive.

Know when to use seasonality adjustments (and when not to)

If you’re using Smart Bidding, it already accounts for many seasonal patterns. Seasonality adjustments are an advanced lever intended for short, exceptional events where you expect a significant conversion-rate change (think flash sales, short promotions, or launch windows). They’re generally best kept to very short periods (often around 1–7 days) and are not a great tool for “the whole month is slow,” especially if you’re stretching them beyond two weeks.

Just as important: if performance dropped because conversion tracking broke or offline conversion uploads failed, that is not a seasonality-adjustment situation. That’s a data-quality situation. In those cases, the correct lever is a data exclusion so Smart Bidding doesn’t learn from bad conversion data. Data exclusions are designed for conversion data outages and apply to clicks (so you must choose dates that cover the affected clicks, taking conversion delay into account). They are not meant to be used frequently or as a way to “smooth” normal promotional volatility.

Year-round improvements that reduce seasonal volatility without chasing ghosts

To make seasonality less painful, focus on the fundamentals that give you more auction resilience. Stronger ad relevance and landing page alignment protect Ad Rank when competitors bid up. Cleaner campaign segmentation (so you can shift budgets to the pockets that still have demand) prevents you from dragging the whole account down during a seasonal dip. And realistic, flexible targets in Smart Bidding help the system keep participating in auctions instead of throttling spend when performance temporarily shifts.

Finally, keep your diagnosis muscle sharp: anytime performance drops, make Change history review a habit. It stores a multi-year trail of edits and makes it much easier to separate “the market changed” from “we changed something,” which is the fastest path to the right fix—whether this drop is truly seasonal or not.

When you’re trying to confirm whether a performance dip is true seasonality or something account-related, it usually comes down to quickly tracing where the drop starts (impressions vs. impression share vs. conversion rate), comparing week-over-week and year-over-year patterns, and checking auction and change-history signals before drawing conclusions; Blobr is designed to make that investigation easier by connecting to your Google Ads account, monitoring performance continuously, and using a set of specialized AI agents to spot what changed, separate market shifts from controllable issues (like budgets, bids, targeting, tracking, or disapprovals), and turn the findings into clear, prioritized recommendations you can review and apply on your terms.