What does the festive season actually do to your ad costs?
Ad auctions are priced by competition. When thousands of Indian brands switch on festive campaigns in the same six weeks, the number of advertisers chasing each impression jumps, and CPM, the cost per thousand impressions, climbs with it. Reported festive increases run 20 to 60% across the season, and in the concentrated sale windows around Big Billion Days, Amazon's sale and Diwali itself, costs can roughly triple.
The important thing is that your product did not get worse and your creative did not get weaker. The same campaign that returned a comfortable ROAS in August can look broken in late October purely because you are paying two to three times more to reach the same person. Nothing about you changed. The room just got crowded.
This is why a flat "spend more during Diwali" plan quietly destroys returns. You are scaling budget into the exact moment the platform is charging its highest rate of the year.
- Festive CPMs rise roughly 20 to 60% across the season
- Sale windows around Big Billion Days and Diwali can push costs up to three times normal
- Your ROAS can fall even when your creative and product are unchanged, purely on cost
- Blindly scaling budget at peak funds the auction, not your growth
When should you actually start your Diwali campaign?
The best-run brands start festive planning in August and use September for the real groundwork, so that by the time costs peak, the expensive learning is already done. Purchase intent builds from September and peaks across Dhanteras and Diwali in early November, which means the audience is warming up well before the sale, and so should you.
Starting in August buys you the one thing you cannot buy at peak: cheap data. Every rupee you spend testing creative in August teaches the algorithm at a fraction of the November cost. Brands that wait until the sale to start testing are paying triple to learn things they could have learned for a third of the price two months earlier.
So the honest answer to "when do I start" is: now, if it is August or September. Not to sell hard, but to test, to build audiences, and to get your tracking and creative sorted while impressions are still cheap.
What is the six-week festive plan, week by week?
Treat the festive season as a sequence, not a single push. Each phase has a different job, and doing them in the wrong order is what leaves brands overpaying in November for work they should have finished in September.
The shape below is what I run: test early while it is cheap, build the audiences and owned channels through September, harvest the warm demand as the sale approaches, and stay disciplined during the most expensive days instead of throwing budget at them.
- August, test: run creative experiments while CPMs are low, find your two or three winning angles
- Early September, build: assemble retargeting and lookalike audiences, fix tracking, set up email and WhatsApp flows
- Late September, warm: start prospecting campaigns so the pixel and audiences are primed before costs climb
- October, harvest: scale the proven winners into the warm audiences you built, watch ROAS daily as CPMs rise
- Dhanteras to Diwali, hold: lean on retargeting and owned channels, avoid burning budget on cold prospecting at triple cost
- Post-Diwali: capture the late shoppers and returns-driven demand while costs cool back down
Why does front-loading beat scaling up at peak?
Meta and Google campaigns need data to perform, and data has a price that changes with the season. When you test in August, each result costs you the August rate. When you test in the Diwali window, each result costs you up to three times as much. Same learning, triple the tuition.
There is a second reason. A campaign that starts cold in late October is asking the algorithm to learn who your buyer is during the most expensive, most competitive week of the year. A campaign that started warm in September already knows, so at peak it is spending on people likely to buy, not on exploration. That difference is the gap between a festive season that prints money and one that just prints invoices.
This is exactly how the strongest D2C accounts I have worked on treat it. Front-load the testing in the quiet weeks, then let the peak be about harvesting, not discovery.
How do you hedge against rising CPMs with owned channels?
The cheapest audience during Diwali is the one you already own. Email, WhatsApp and SMS cost you nothing per impression, and they reach people who already know you. Brands that build these lists before the rush lean on them during peak, when paid reach is at its most expensive, and cut their dependence on the auction at the worst possible moment to be dependent on it.
September is when you build this. Grow the list with the traffic you are already buying cheaply, set up your festive flows, and segment your past buyers so that on Dhanteras you can send an offer to people who cost you nothing to reach instead of bidding triple to find new ones.
None of this replaces paid. It gives you somewhere to lean when paid gets expensive, so you are not forced to overspend just to keep sales moving through the peak.
- Build email, WhatsApp and SMS lists in September using cheap pre-season traffic
- Set up festive flows and segment past buyers before the sale, not during it
- On peak days, message your owned list first, then top up with retargeting
- Use owned channels to reduce reliance on the auction when CPMs are highest
What if you're reading this in October already?
If the quiet weeks are behind you, do not try to run the full playbook late. Skip cold prospecting at peak cost and put your money where it still works: retargeting people who already visited, and your owned channels. Warm audiences convert at a price you can live with even when CPMs are high.
Tighten to your proven winners. This is not the week to test five new creatives at triple the cost. Run the one or two angles you already know convert, cap your prospecting, and let retargeting and email carry the peak.
Then make a note for next year: block out August. The single highest-return festive decision is one you make ten weeks early.