Is there any way I can use the temperature data from my Tempest to turn off the A/C on my Nest thermostat? I’d like to setup some sort of automation when the outside temperature reaches 60 degrees it will turn off the cooling on my Nest.
You will need a home automation hub like Home Assistant or Habitat to connect to both to your weather station data and the Nest thermostat. Then you can write automations that says like:
If outdoor temperature from Tempest is > 75 degrees change mode of Nest to Cooling
You may want to poke around in their forums: