Seasonality
Seasonality is a predictable pattern in which demand rises or falls at the same times each year, driven by holidays, weather, school calendars, or shopping events.
Why it matters for ecommerce brands
Seasonality sets when you must commit cash to inventory, often months before demand arrives. Most US ecommerce brands do a large share of annual sales in Q4, so seasonal purchase orders go out long before the peak. For example, a brand selling 40% of its 50,000 yearly units in November and December needs about 20,000 units received by late October. With 60 days of production and 45 days of transit and receiving, that PO must be placed by mid-July. Plan what you will do with leftovers before the season starts.
Common questions
- How do you account for seasonality in inventory planning?
- Build forecasts from the same period in prior years, adjusted for growth, rather than recent weeks alone. Then work back from the peak by your full lead time, including production, ocean transit, and receiving, to set purchase order dates.
- What is the difference between seasonality and a trend?
- Seasonality repeats at the same time each year, such as a December peak. A trend is a longer-term rise or fall in demand, so forecasts should separate the two before projecting growth.
- How early should I send inventory to my 3PL for the holiday peak?
- Receiving slows at many 3PLs near peak, so ask yours for its peak inbound cutoff and plan for stock to be received and sellable several weeks before Black Friday. Late inbound freight can sit at the dock during your busiest weeks.