Swansea open their PL season away on Aug 12th at Southampton.
With Swansea and Cardiff playing opposite each other almost every matchday (there are a some exceptions) we can work out that Cardiff should be at home that day.
The Championship season kicks off a week earlier on Aug 5th and the way historical fixtures show us if a team is away on the opening day they are home for their second fixture. So if we are going to be at home on Aug 12th then a week before we will be away.
Looking further ahead it looks like Boxing Day will be a home fixture (opposite Swansea who are away) and also our last game of the season could be at home (as Swansea are away that weekend as well).
Cardiff are likely to be away on New Years Day if the pattern is correct.
The fixtures for the FL clubs will be announced on Wednesday 21st June.