I am trying to the following. Not sure if there is an app or how to do it in ST. I can do this with IFTTT but I cannot tell IFTTT do not fire if none is at the house.
Is there a way I can read the temperature from outside (using SmartWeather Tile 2.0) and make that the trigger to turn on the fan (or really any switch)?
Sure, this is pretty basic home automation. I am assume you are referring to this device handler right?
I just tested it using Virtual Thermostat smartapp and it worked fine for your application.
Thanks. I will try the Virtual Thermostat app.