My partner and I are thinking of doing a whale shark tour from Tulum. However, we'll be in Tulum from 12 May to 22 May. There seems to be some discrepancy for when the whale sharks are actually there. There are a lot of references to that start of the whale shark 'occupation' in June, but then some tour companies state from mid-May. So the question is, are the tour companies saying mid-May to sucker a few extra tourists?