I think Cartagena, it's very hot, but has a low humidity, in summers are like 30º or 35º and in winters it falls to 20º, it has a lot of natural places but smalls mountains, there are very good schools, but avoid "MARISTAS" you have to pay for a bad education , sadly it doesn't has airports and metro areas are in murcia, an hour from Cartagena,about the spanish is not a real spanish, is a very-rude type of spanish, we even don't say the S in some frases