One of the better short-haul flash sales offered by JetBlue. Works in reverse SJC -> LGB as well.
Fare Availability & Sample Date
January 2017. Both weekday (Mon/Wed/Thurs) and weekend (Sat) departures available. Great availability on both dates and times.
Sample date: January 21-25, 2017, check for others using Google Flights.
Booking Tips
Use Google Flights, then book directly on JetBlue. Long Beach is about ~30 min south of LAX (without traffic), and San Jose is ~1 hour south of San Francisco (also, without traffic). CalTrain makes it easy to get around the Peninsula on public transit, though LGB isn’t as well connected on the LA Metro.