Abstract: Disclosed are systems and methods for determining the best time to send an electronic communication from a sender to a recipient. In one aspect, a method is disclosed that includes selecting a time window from a series of candidate time windows based on a corresponding first value for each candidate time window, wherein each first value is representative of a likelihood of receiving an event notification within a specified first delay after the candidate time window. The method further includes selecting a time period from a plurality of time periods within the selected time window based on a corresponding second value for each time period representative of the likelihood of receiving the event notification within a specified second delay after the time period. The method further includes generating a signal indicative of a time within the selected time period at which an electronic communication should be sent.