Hello, super new to Home Assistant so this may be a very basic question. One of the things that got me fed up with HomeKit was the lack of variability during the year. For example during the summer/spring I have an automation that triggers a scene that sets the temperature in the morning, but then in the fall/winter I want that to be heat. In HomeKit I have to go and change all the “sunrise” automation manually when the weather changes.
Is this doable in Home Assistant?
Welcome! 
That depends on what criteria you want that to change. Eg. do you want that depending on specific months, on weather, the metereological calendar or …?
But yes, you can do that in HA, in many differnt ways or with different methods. Let us know more about what you want to achieve, and what your criterias are.
what about using the Season integration with the sun integration