What are techniques for forecasting daily sales for a 14 day interval? Note, my historical data is 14 days of daily sales data that may or may not have fallen in the same month (e.g. July 2017) as the interval I am trying to forecast for (e.g. July 2018).
Daily sales typically exhibit intra-weekly seasonality. However, you have very little data to fit this reliably. You basically have two choices:
- Use the overall historical mean. Note that the overall mean can be surprisingly hard to beat in terms of accuracy.
- To forecast a Tuesday's sales, take the average sales for the two Tuesdays you have in your history, and so on for the other days.
Since you have very little data, the second approach may be unstable, so there is a good chance the first one will be better. If there is any way you could obtain more data, do so.
We have quite a few prior threads on daily forecasting. Consider browsing through these.