It is disclosed a weather-predictive apparatus for controlling a climatization plant, comprising a weather-climate data sensor associated with a building, a processing unit and a signal transceiver. The signal transceiver is configured to transmit a current measured value of the weather-climate data associated with the building to a weather forecast device and it is configured to receive from the weather forecast device a plurality of weather forecast data associated with the building in a forecast time interval. The processing unit is configured to: calculate a change in a nominal activation instant of the climatization plant of the building, calculate a modified activation instant; check whether the current instant is equal to the modified activation instant. In case wherein the current instant is equal to the modified activation instant, the processing unit is configured to generate a command signal having a value representative of the activation of the climatization plant.