Partial match: Descendentes or Solos, a 2008 Chilean movie.
In an undefined future, the earth has been destroyed by man, and the air polluted with a mysterious virus that turns humans into zombies. Only a few children are immune to the disease and have adapted to these extreme conditions and survived. Camille, a nine year old girl wanders through these desolate wastelands, protecting herself from zombies and the armed military forces that roam the land killing anyone who might be infected. However, the little girl will find other kids like her that share a recurring dream of: they all have visions of the ocean as their destiny. Together they will try to survive the journey to the ocean in search of an escape from the military who seem to be as determined on their destruction as on the zombies.
Warning, the trailer is very graphic:
I'm putting it as an answer as there does not seem to be many zombie movies with a "survivors must go to some beach" plot, so it may be useful to future readers; however, it's probably not the exact movie the question is referring to, as the children travel to the beach not because of winds hindering, but because the main character's dying mother instructed her to.
Found with the query
future portal zombie on whatismymovie.com, filtered by "Traditional search" results; I was actually looking for an answer to Movie: in a big seaside city time travel portals open to the apocalyptic future with the fading sun and zombie mutants, but the bit about the ocean made me remember the present question.