Yucatan is one of the major holiday destinations in Mexico. It is the peninsula in the southeastern corner of the country. Almost always sunny, adorned with Mayan ruins, and mass tourism: Yucatan has it all.
It’s important to make a distinction between the peninsula and the province. Because the latter only covers part of the peninsula (although the most important tourist sites such as Cancun, Playa del Carmen and the Mayan ruins of Chichen Itza).
There is though much more to the area. Campeche is much quieter, with the city of Campeche itself with its lovely walled city center as a focal point. But here you can also go for the Mayan ruins of Calakmul. Campeche province is also the connector if you are coming from (or want to go to) the jungle ruins of Palenque.
Quintana Roo is the third province on the peninsula. This is where Tulum, with its old fortress ruins, is located. Tulum has become a hippie paradise. Much further south though, really off-the-beaten-track and almost in Belize, is Lake Bacalar, an amazing hide-out.
Thus, plenty to do in Yucatan. It is extremely humid, there is a hurricane season (mainly August-October) to take into account, rain can be expected throughout the year in bursts though. And plenty of sun as well.
If you want to know more, read the detailed articles to the different places: