A power management system includes: customer terminals; and a power management apparatus connected to the customer terminals, wherein each of the customer terminals includes a weather forecast acquisition unit that acquires a local weather forecast for a corresponding customer terminal, and a power prediction unit that predicts a power consumption and an amount of power that can be reduced for a predetermined period based on the weather forecast, and the power management apparatus includes an integration processing unit that integrates the power consumptions and the amounts of power that can be reduced that are predicted for the respective customer terminals to calculate a total power consumption and a total amount of power that can be reduced for all of the customer terminals.