1. A method in a computing device for forecasting frequency of a time-dependent query, the method comprising: for each of a plurality of past intervals, storing frequency of the query at the past interval, the stored frequency for an interval representing number of times the query was submitted during the interval; calculating a value of a frequency spectral of the query for each of a plurality of angular frequencies based on frequencies at the past intervals; identifying one or more peaks within the frequency spectral; generating, for a model, parameters for each identified peak, the generated model providing an estimated frequency of the query at an interval based on a contribution to the estimated frequency derived from each identified peak, wherein the model is based on a cosine signal hidden periodicity model; for each of a plurality of future intervals, determining a forecasted frequency at the future interval based on the model parameters generated for the model by summing the contributions to the estimated frequency derived from each identified peak; and storing an indication of the determined forecasted frequency.