April is the changeover. Through the winter the Mexican Pacific runs on north and north-west swell out of the North Pacific; from April it flips to south and south-west swell generated in the Southern Ocean, and it keeps that until October. One turn of the ocean moves the whole country's season from one end to the other.
For a traveller the practical version is simple. Until now the answer has been Nayarit; from the end of this month it becomes Oaxaca. April itself sits across the join, which makes it a genuinely uncertain month to book and an interesting one to already be in: both coasts get something, neither has a pattern.
Puerto Escondido starts waking up now. Zicatela is not yet what the summer makes it, and for anybody who wants to see that wave without meeting it, April and May are the sensible weeks.
