Oceanside is well known for their waves and surf culture. Every year, crowds flock to Oceanside in search of great weather and waves.
The large jetty to the North of the beach during a strong South swell produces some amazing rights that peel off into the beach. On the South end of the beach is another jetty (smaller) which also produces some really fun waves with the right conditions.
What swell do you want to look for? South-Southwest and West-Northwest swells typically produce the best waves with the southwest swell producing the most ideal surf conditions. As far as the tides are concerned, look for medium to high tides for the best surfing conditions.