Moon
Phases and how they pull the water.
The moon pulls the water
The tide is the moon's gravity, mostly. New and full moons align sun and moon for the biggest swings — spring tides. Quarter moons temper them into neaps.
Phases to watch
new spring tide — big swing full spring tide — big swing first/last quarter neap — small swing perigee closest moon — biggest of all
For surfers
Big swings move more water, which can wake up a sleepy break — or bury it. Learn your spot's response.