Seasonal sales, when do you have to buy the stock to have it available?

One of the main reasons for doing Time Series Analysis is to be able to work out when your sales are likely to be when you have a seasonal product. knowing when your sales are allows you to know when you have to make things/buy things to have them available for sale.

Here’s an interesting example for a product only used in winter – snow blowers in the USA – note when the company buys them.