You can connect smart shades to devices like Nest. The shades then respond to the temperature in the room. For example, if it gets above 75 degrees (or whatever temperature you prefer), you can program the shades to close.

I prefer not to use appliances associated with Google's networked devices. Are there any shades with self contained sensors?

We only sell Hunter Douglas brand shades, so I'm not familiar with other brands.

With the Hunter Douglas PowerView Hub, you operate the shades through the app. You can program schedules for different shades. For example, if you know your house gets intense sun starting at noon, you can program the shades to close at 12pm and re-open once the sun sets.

You can also operate the shades remotely. So, you could be at work and close or open the shades depending on weather conditions.

Yes and no, Hunter Douglas PowerView motorized shades can be programmed through a hub and the app to tell the shades to open and close according to sunrise and sunset.

As far as opening and closing on sunny days vs. cloudy days, they do not offer a solar sensor for that kind of automation.

L&L is correct. The best way to compensate for the sunny days vs. cloudy days would be to program a "scene" in the app that would be fully open or fully closed according to those days so that you can simply operate them by a click of the button in the app.

You could do this through a smarthome hub like Samsung Smarthings. You would probably need to use a Lux sensor to determine the brightness, or integrate it with IFTTT and a weather source to determine sunny/cloudy days.

More info here