Weather-predictive apparatus for controlling a climatization plant, the apparatus comprising a sensor of weather-climate data associated with a building, a processing unit and a signal transceiver, wherein: - the signal transceiver is configured to transmit, to a weather forecast device through a telecommunications network, a current measured value of the weather-climate data associated with the building; - the signal transceiver is configured to receive, from the weather forecast device through the telecommunications network, a plurality of predictive weather data associated with the building in a forecast time interval starting from the current instant, wherein said plurality of predictive weather data are calculated as a function of the current measured value of the received weather-climate data associated with the building and as a function of weather forecasts associated with the building in the forecast time interval; - the processing unit is configured to: • calculate a change in a nominal activation instant of the climatization plant of the building, as a function of the value of at least part of the plurality of the calculated received predictive weather data; • calculate a modified activation instant as a function of the value of the nominal activation instant and of the value of said change in the nominal 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, generate a command signal (S_en) having a value representative of the activation of the climatization plant; • in case wherein the current instant differs from the modified activation instant, repeat the calculation of the change in the nominal activation instant, the calculation of the modified activation instant and said check until the current instant is equal to a further modified activation instant, generating the command signal when the current instant is equal to the further modified activation instant. - the signal transceiver is configured to transmit, to a weather forecast device through a telecommunications network, a current measured value of the weather-climate data associated with the building; - the signal transceiver is configured to receive, from the weather forecast device through the telecommunications network, a plurality of predictive weather data associated with the building in a forecast time interval starting from the current instant, wherein said plurality of predictive weather data are calculated as a function of the current measured value of the received weather-climate data associated with the building and as a function of weather forecasts associated with the building in the forecast time interval; - the processing unit is configured to: • calculate a change in a nominal activation instant of the climatization plant of the building, as a function of the value of at least part of the plurality of the calculated received predictive weather data; • calculate a modified activation instant as a function of the value of the nominal activation instant and of the value of said change in the nominal 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, generate a command signal (S_en) having a value representative of the activation of the climatization plant; • in case wherein the current instant differs from the modified activation instant, repeat the calculation of the change in the nominal activation instant, the calculation of the modified activation instant and said check until the current instant is equal to a further modified activation instant, generating the command signal when the current instant is equal to the further modified activation instant. • calculate a change in a nominal activation instant of the climatization plant of the building, as a function of the value of at least part of the plurality of the calculated received predictive weather data; • calculate a modified activation instant as a function of the value of the nominal activation instant and of the value of said change in the nominal 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, generate a command signal (S_en) having a value representative of the activation of the climatization plant; • in case wherein the current instant differs from the modified activation instant, repeat the calculation of the change in the nominal activation instant, the calculation of the modified activation instant and said check until the current instant is equal to a further modified activation instant, generating the command signal when the current instant is equal to the further modified activation instant.