The present invention may be embodied as expected event scheduler and processor in an application performance monitoring (APM) services. The expected event scheduler and processor allows the APM system to take scheduled events into account when performing the performance forecasting for the host system. The learned parameters may be based on measured input values including internal measurements, such as data from monitoring agents located within the host computer system, as well as external measurements relating to factors such as computer backup runs, monthly payroll runs, quarterly financial reporting runs, weekends, holidays, weather data, traffic data, advertisements run by the operator of the system or others, promotional events, product releases, news announcements, elections and other natural and demographic factors. The expected events may overlap in time, and the expected event scheduler and processor learns weighing factors for the simultaneously occurring expected events by updating the learned parameters over successive time trials.