Google Ads Seasonality Adjustments: How to Handle Black Friday & Flash Sales (2024)

The Scenario: It is Black Friday. You launch a "50% Off" sale for 48 hours. Your Conversion Rate (CVR) is normally 2%. You expect it to jump to 6% (3x) during the sale.

The Problem: Smart Bidding (tROAS) looks at the last 30 days of history. It thinks your CVR is 2%. When the sale starts at midnight, Smart Bidding bids normally. It misses the surge. By the time it "learns" that CVR is 6%, the sale is over. Then, on Sunday (when CVR drops back to 2%), it keeps bidding aggressively and wastes money.

The Solution: Seasonality Adjustments. You explicitly tell Google: "Listen up. Between Friday 00:00 and Sunday 23:59, expect CVR to increase by +200%."

Part 1: When to Use It (And When Not To)

USE IT IF:

1. Short Duration: The event is 1-7 days.
2. Major Change: You expect CVR to change by >30%. (Flash Sales, influencer drops, TV appearances).

DO NOT USE IT IF:

1. Long Duration: "Christmas Season" (Dec 1 - Dec 25). Smart Bidding handles gradual seasonal shifts naturally.
2. Small Change: A mild "10% off" weekend.
3. Permanent Change: "We lowered our prices permanently."

Part 2: Setup Guide

1. Navigate: Tools & Settings → Bidding → Seasonality Adjustments.
2. Create New:
   • Name: "Black Friday 2026".
   • Start/End: Fri 00:00 to Sun 23:59.
   • Scope: The specific campaigns running the sale.
   • Adjustment: Conversion Rate will increase by +200% (i.e., 3x).
3. Save.

Part 3: The "Post-Sale" Hangover

This tool is critical for the Day After. Without Seasonality Adjustments, Smart Bidding sees the huge spike on Friday and thinks "Wow, this audience is amazing!" On Monday, it will bid aggressively, thinking the party is still going on. It will crash.

With Seasonality Adjustments: The moment the adjustment ends (Sunday 23:59), the algorithm instantly reverts to its pre-sale behavior. It ignores the Friday spike for future calculations. It "forgets" the anomaly.

Summary

This is the most under-used tool in Ecommerce. If you rely on Smart Bidding, you cannot rely on it to guess your marketing calendar. Communicate with the machine. Tell it when the party starts, and more importantly, when it ends.