How to manage seasonality in e-commerce

Until recently, seasonality in e-commerce was straightforward and predictable. New Year, Black Friday, the summer slump, the autumn upturn - businesses planned their sales around the calendar and drew on past experience.

But this logic no longer holds true, according to experts at Halla Systems. Seasonality today can be driven by basic algorithms for parsing and comparing prices. And it may have nothing to do with specific dates. Consequently, businesses have to view seasonality in terms of short-term demand scenarios: a build-up, a sharp sales peak, a post-holiday slump with returns, and localised spikes. Retailers are increasingly taking regional rather than calendar-based events into account, linking seasonality to the weather and local traditions.

Experts at Halla Systems dropshipping note that the biggest misconception in e-commerce is to regard seasonality as an external factor. It is often created within the company itself: through discounts, product quality, delivery terms and the way logistics are organised.

In 2026, it will be important for businesses to identify not simply the ‘fact of the season’, but the point at which profit is lost. This involves analysing not absolute figures or ‘how much was sold’, but how rapidly demand changed. When this is achieved, seasonality ceases to be a risk and becomes a manageable system.

First question: is demand growing organically or is it being driven?

The most common mistake is to regard any increase in sales as seasonality, warn the experts at Halla Systems dropshipping. In practice, this is almost never the case. If sales are rising simply because you’ve introduced a discount, stepped up advertising, or a marketplace has provided extra visibility, this isn’t a seasonal trend. It’s the ‘push-button effect’. As soon as you ‘let go’ of it, the growth disappears.

The test here is simple and straightforward: what happens to demand when conditions return to normal? If sales hold up, it means people genuinely need the product right now. If they fall, it means it was a temporary spike, not a peak season.

Second question: is the growth continuing or already coming to an end?Another pitfall is looking at the final figures for the month or quarter. By that point, the season has either already ended or a downturn is already underway. It is far more important to track how sales change from week to week – not in absolute terms, but in terms of trends. If growth is slowing, even with high volumes, the season is nearing its end. If it is accelerating without any extra effort, it is only just beginning.

Companies that monitor these trends enter the season ahead of their competitors and exit it before margins start to erode.

Question three: who exactly is buying?

Seasonality is almost never ‘universal’. Most often, it applies to a specific target audience and a specific period, according to experts at Halla Systems. If growth is driven mainly by new customers who have come on board following an advertising campaign or via a marketplace, such demand rarely repeats itself. If, on the other hand, those already familiar with the brand start buying more actively, the season is usually more stable and longer-lasting.

Essentially, measuring seasonality here boils down to a simple observation: do customers return without any additional incentives? If so, it is a genuine season. If not, it is a one-off event.

Why marketplaces create a false sense of seasonality

Marketplaces are adept at making growth look very convincing. Products gain visibility, sales soar, and the figures look impressive. But this growth often lasts only as long as the platform’s support does.

That is why a rise in sales on a marketplace cannot automatically be taken as a sign of a genuine market season, warn the experts at Halla Systems dropshipping. The most reliable test is to see what happens when the product is no longer actively promoted. If demand remains unchanged, the season is genuine. Otherwise, sales were driven by the algorithm, not the market.

Seasonality. What to do today: a 30-day plan

Week 1

Compile the following metrics into a single table:

turnover
number of orders
average spend per order
conversion rate
advertising spend
profit after key expenses (margin)
proportion of sales at a discount
returns (number and value)
availability of key products
proportion of new and repeat customers

Week 2

Break down sales:

at a discount / without a discount
by channel
by 20 key products

Week 3

Run 1–2 A/B tests (a promotion or advert targeting a limited audience segment)

a new discount format (e.g. not ‘15% off everything’, but ‘discount when buying 2 items’)
Adjust the advertising volume (e.g. increase or decrease the advertising budget by 20% for a short period)
Improve the product page (e.g. rewrite the headline and description, add clear photos, delivery times and return conditions) for a selected group of products

Week 4

Compare the results in terms of profit, not just turnover
Keep only what has generated a real increase in profit

Halla Systems recommends: Post-season analysis

Once peak periods are over, it is important to understand what generated profit, which channels clashed and which influenced demand, and how much business was lost due to stock shortages or excessive discounts. Seasonality must be managed: with a weekly rhythm, standardised metrics, tests prior to scaling, and a focus on actual profit.