A master HVAC schedule for an HVAC controller may be stored on an external server accessible over a computer network. The external server may maintain the master HVAC schedule, and may translate a portion of the master HVAC schedule into a basic HVAC schedule that is executable by an HVAC controller. The external server may deliver the basic HVAC schedule to an HVAC controller according to a predetermined schedule. In some cases, the external server may deliver an updated basic HVAC schedule to the HVAC controller in response to a user initiated change made to the master HVAC schedule or upon restoration of a lost network connection between the HVAC controller and the external server.