How do you plan production for a seasonal peak?

Production for a seasonal peak is planned by comparing the seasonal demand forecast with production capacity month by month, then working backward from the peak to find how much has to be built in earlier months. The plan is then checked against raw material lead times, shelf life and the working capital the pre-built stock will tie up.

How early should a manufacturer start building for a seasonal peak?

A manufacturer should start building in the first month that the backward capacity calculation says is needed, then move earlier by the raw material lead time, because materials have to arrive before the first run. Products made at a co-manufacturer also need production windows booked before the co-man's calendar fills with other brands' peaks.

How is seasonal planning different at a co-manufacturer?

Seasonal planning at a co-manufacturer is built around booked production windows rather than continuous capacity. Each run has to cover demand until the next window, plus safety stock. Missing a window can mean waiting weeks for the next one, so the brand books windows early and plans materials to arrive at the co-man before each run.

Does shelf life limit how early a seasonal build can start?

Shelf life limits a seasonal build because stock made too early may not have enough remaining life when it reaches the retailer. Retail buyers often require a minimum remaining shelf life on delivery. The earliest build date is the date that still leaves enough life for the retailer's requirement plus the time the product spends in the channel.

What should a manufacturer do if peak demand exceeds capacity even with a pre-build?

A manufacturer whose peak demand exceeds capacity even with a pre-build can add shifts or a second co-manufacturer, start the build earlier, simplify the range in the peak, or decide in advance which accounts and channels receive limited supply. The allocation decision should be made and communicated before the season, not during it.

Seasonal Production Planning, Step by Step

What has to be true before a seasonal build starts?

A seasonal build works only if four things line up months before demand arrives. Each one has a different owner and a different lead time.

Input	Question	Usually owned by
Seasonal demand forecast	How much will each SKU sell in each month of the peak?	Demand planning
Production capacity	How much can we make each month, on our lines or at the co-man?	Operations, co-man
Raw materials	Will every ingredient and packaging component arrive before its run?	Purchasing
Cash and space	Can we fund and store the stock built ahead of demand?	Finance, warehouse

The forecast comes first, and it has to be per SKU, with growth and promotions separated from the seasonal pattern. How to forecast demand for seasonal products covers building it.

How do you size a pre-build against capacity?

Start from the peak month and work backward. In each month, if demand plus the stock you need to carry into the next month is more than you can make, the difference has to be built the month before.

For example, suppose a line or co-man allocation can make 60,000 units a month, and the seasonal forecast is 40,000 in September, 45,000 in October, 70,000 in November and 85,000 in December.

Hypothetical plan	Sep	Oct	Nov	Dec
Demand	40,000	45,000	70,000	85,000
Capacity	60,000	60,000	60,000	60,000
Stock needed at month end	20,000	35,000	25,000	0
Production	60,000	60,000	60,000	60,000

Working backward in that example: December is 25,000 short, so November has to end with 25,000 in stock. November then needs 95,000 against 60,000 of capacity, so October has to end with 35,000. October needs 80,000, so September has to end with 20,000, which September's spare capacity covers. The build starts in September, and stock peaks at 35,000 units at the end of October.

Add safety stock at each month end and the build starts earlier. If the first month's requirement is more than capacity, the plan does not fit, and you need more capacity, an earlier start, or a smaller commitment to the peak.

Do the calculation per SKU, then per line

The calculation above is for one product on one constraint. A real plan has many SKUs sharing a line or a co-man's time, so total the monthly production of every SKU that shares a constraint and check that total against capacity. Changeovers and cleaning between products reduce the usable time on a line, and allergen sequencing can limit which products run back to back.

How does the plan change at a co-manufacturer?

At a co-manufacturer you plan around booked production windows rather than a monthly capacity figure. The arithmetic changes in three ways:

Each run covers demand until the next window, plus safety stock, not just one month.
Windows are booked in advance, and other brands with the same peak are booking them too. Ask for the peak-season calendar early.
Run sizes have limits. A co-man will have minimum run quantities and may cap the maximum, which can force a larger early run or an extra window.

The brand also has to know what stock the co-man holds, of both finished goods and materials, before each run. Co-packer inventory management covers keeping that figure accurate.

When do the raw materials have to be ordered?

The first run of the build cannot start until every material on its bill of materials has arrived. For each material, the order-by date is the run date minus supplier lead time, transit, and receiving or quality hold.

Packaging usually sets the date. Printed film, cartons and labels often carry the longest lead times and the largest minimum order quantities.
Shared materials need one combined plan. A seasonal build pulls the same ingredients forward for several SKUs at once, so net the total requirement against stock once.
Suppliers have peaks too. Confirm that a supplier can deliver the seasonal volume, not just its usual lead time.

How to calculate raw material demand works through the calculation, including the shared-material netting.

What does a seasonal build cost?

Building ahead moves cost earlier. Check three things before committing.

Working capital

The pre-built stock and the materials bought for it are paid for before the peak revenue arrives. For example, at a unit cost of $4, the 35,000 units in stock at the end of October in the example above hold $140,000 of working capital, before counting materials bought for later runs. Finance needs that figure months ahead, not when the build is already running.

Shelf life

Consumable products have a shelf life, and retail buyers often require a minimum remaining life on delivery. The earliest month you can build is set by the shelf life, the retailer's requirement and the time the product spends in the channel. For short-life products, add capacity in the peak rather than building early.

Space

Pre-built stock has to be stored somewhere. Check warehouse or 3PL space for the month the stock peaks, which is usually just before the peak demand month, not the peak itself.

How do you plan the end of the season?

The risk at the end of a seasonal peak is the stock built for it. Plan the last runs to finish before demand falls, and size them against the latest forecast rather than the one used to book capacity.

Re-forecast before each late run and cut the run if sell-through is behind.
Decide in advance what happens to excess: a planned promotion, a channel that can absorb it, or a write-off budget.
Agree allocation rules before the season for the case where demand runs ahead of supply, so the decision about which accounts are short is not made under pressure.

How Planster supports seasonal production planning

Planster provides the demand and materials side of this plan. It forecasts each SKU from its own history with a statistical model chosen for that SKU, detects seasonality per SKU, and alerts you ahead of a seasonal peak allowing for lead times. Bills of materials show which production runs are coming and what materials each one consumes, so shared components are planned once. See bills of materials and kitting.

Before you commit to a promotion or a new retailer during the season, scenario planning shows the purchase orders and cash it would commit, so the cost of the build is visible before anyone approves it. See scenario planning. Purchase orders are drafted for your team to approve. The production schedule itself is set by your team with your co-manufacturer or on your own lines.

Seasonal Production Planning: Building Ahead of a Peak