I have a window fan in my bedroom that, in the warm season, I have set to turn on automatically at 9:00 p.m. via a Wemo outlet.

That’s great. Except when it’s not, because the weather turns cold, and the last thing I want to do is suck 14ºC air into my bedroom.

So I created an iOS Shortcut to turn the fan on only if the temperature is more than 17ºC.

The Shortcut uses the Weather app on the phone to get the current weather, and then checks to see if the current temperature is more than 17ºC; if it is, it turns on the fan:

I then added this to a “Personal Automation” in the Shortcuts app, to run every day at 9:00 p.m.:

I could make this smarter if I had a way of reading the indoor temperature too (my Nest thermostat knows the temperature, but because of Balkanization, it won’t talk my iPhone).