My husband and I go to Puerto Vallarta every January and the weather is quite wonderful - clear blue skies and quite warm weather - it is definitely warm enough to go in the ocean - as a matter of fact, sun lotion and hats are very much needed depending how fair you are. In the evenings it may be a bit cool once the sun goes down and a sweater may be required. It is a nice place to be in January.

Carol Toronto, Canada