Inventory Planning for Seasonal Demand
Seasonal demand is predictable. Seasonal inventory problems are not inevitable they are the result of predictable demand being met with reactive planning. The brand that plans its Diwali inventory in October is already too late. The brand that planned it in August has the right stock, in the right channels, at the right cost.
Nirmal Nambiar
Author
Seasonality is the most predictable form of demand variation a calendar-driven pattern that repeats year after year with knowable direction and approximate magnitude. Yet the stockout during Diwali, the dead stock after Valentine's Day, and the cash crunch in January following a December overstock are perennial features of D2C and FMCG operations in India. They are perennial not because seasonality is unpredictable but because the planning lead time required to position inventory correctly for seasonal peaks is longer than most brands accommodate. The Diwali pack that needs to be in channel by October 1st needs production completed by September 10th, raw materials purchased by August 20th, and the production order placed by July 30th. The brand that begins thinking about Diwali in September has already missed the production timeline for October channel positioning.
The Seasonal Inventory Planning Timeline
The seasonal inventory planning timeline works backward from the channel availability target date the date by which goods must be available in each sales channel to capture the seasonal demand peak. For Diwali (typically a 3-week peak from mid-October to mid-November): channel availability target October 1st. Distribution to retail and marketplace FBA/FBF must be completed by September 25th (5 business days for inbound processing). Goods must leave the warehouse by September 18th (7 days for distribution transit). Goods must arrive at the warehouse by September 10th (8 days for receiving, quality inspection, and stock positioning). Production completion and dispatch from manufacturer must be by August 30th (10 days for transit from manufacturer to warehouse). Production must commence by August 10th (20-day production lead time). Raw materials must arrive at the manufacturer by August 5th (production buffer). Raw material purchase order must be placed by July 10th (25-day raw material lead time from supplier).The Diwali production decision must be made in early July three months before the peak. Most brands make this decision in August or September, which means they are producing in September for goods that should be in channel in October an impossible timeline at most Indian contract manufacturers.
The Seasonal Demand Forecast Methodology
The seasonal demand forecast uses three inputs: the baseline velocity (trailing 90-day daily units sold by SKU by channel), the seasonal index (the ratio of the peak period's historical average daily velocity to the full-year average daily velocity, derived from the prior two years' data), and the growth rate adjustment (the business's expected year-over-year growth rate applied to the seasonal baseline). The formula: seasonal production target = (baseline velocity × seasonal index × seasonal period length × growth rate adjustment) + safety stock buffer.For a SKU with a 45-unit daily baseline velocity, a Diwali seasonal index of 2.4 (based on prior year data showing Diwali peak at 2.4x the annual average), a 21-day peak period, and a 30% year-over-year growth rate: seasonal production target = 45 × 2.4 × 21 × 1.30 + safety stock = 2,948 + 400 = 3,348 units. Safety stock for a high-velocity seasonal event should be calculated at 15% of the base seasonal projection, reflecting the higher demand uncertainty during a concentrated peak period.
Managing the Post-Season Inventory Risk
- Set a maximum post-season inventory policy no more than 10% of the seasonal production should remain unsold 30 days after the peak ends; above this threshold triggers a clearance initiative
- Build seasonal production in tranches rather than in a single committed run 60% of the seasonal forecast at the initial commitment and 40% committed on a 14-day fast-track reorder triggered by in-season velocity confirmation
- Track sell-through velocity weekly during the seasonal peak against the forecast and update the remaining season forecast daily the ability to identify whether the season is running ahead of or behind forecast by week 2 of the peak allows an accelerated reorder or an early clearance decision before excess inventory accumulates
- Plan the post-season clearance pricing before the season begins defining the discount level and channel strategy for post-season clearance in advance prevents the reactive deep discounting that destroys price anchoring when clearance is improvised
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