Depends on where you're from for the second one. I lived there for five months and I'll be going back once visa is sorted.

They have very mild weather, although the memes about cloudy skies and rain are barely memes. It does actually rain/have overcast quite often on that island.

That said. I wouldn't visit the castle if I were you. Too expensive for what is basically office buildings now and was only a fort back in the day. Though walking down the Royal Mile in old town is really nice. Both the main art museum right off Princes Street and the history museum are both fantastic if you enjoy learning. They're also both free. There's the Princes Street Garden which is a fantastic place to relax while you're out and about. If you fancy a trip to the zoo, it's a decent one. Though that'll cost ya. Really just exploring old town is fantastic to do. There's also King Arthur's seat if you fancy a hike and bit of a climb.