According to your yield opportunities, you may decide of a more or a less developed forecasting tool. You may also consider Computerized - Revenue Management System. Here some examples of hotel forecasting tools in exel.
Forecasts are not perfect. It is a strategic management tool. A basic Forecast is better than none. It is the path to market and customer knowledge. It reinforces your pro-activeness in terms of inventory and rate management.
Your forecast module can help to forecast the double occupancy, the number of arrivals and departures: useful for the front-desk and housekeeping. On the basis of your forecasted number of nights by segment, you can anticipate the number of guests: it helps housekeeping to forecast their costs, and the restuarant the number of breakfasts. The forecast can help you to prevent and identify challenges in reaching your objectives: it gives time to adapt strategies or work out additional actions.
The forecast can help to identify low demand period: you can develop it as a communication tool taken over by sales department to focus their efforts on sales.
Basic Forecasting Model
Advanced Hotel Forecast