Thermostat with Timer available?

Setup, Configuration and Use Widgets
3

There is a widget on the marketplace but this requires way more than just a widget so following the tutorial is definitely a must.: Timeline.

As @pacive mentioned, there are several ways you can do this.

  1. Design Pattern: Simple State Machine (e.g. Time Of Day)
  2. Time Based State Machine [4.0.0.0;4.9.9.9]
  3. One way to implement 1 is instead of hard coding the time in the trigger, you can use the Time is Item trigger and set the time in a DateTime Item. You can use DateTime Standalone Widget and DateTime List Item to set the date times.
  4. The timeline picker already linked
  5. iCal binding: iCalendar - Bindings | openHAB