I am lucky to find "Genesis", a French documentary about the natural history of the Earth, on TPS Star tonight. Google takes me instantly to the schedule page of the TPS Star channel, informing me: Genesis Film documentaire de Claude Nuridsany et Marie Pérennou. 2004. Thanks globalization for the poor.
The Earth starts with molten lava.
As the fire burns out, steam comes out.
The steam is redistributed on the lava as rain, covering the earth and cooling it.
As the volume of steam gets redistributed as oceans, seas, rivers and lakes, the weather cycle is initiated.