It's the power and magnificence of the autumn, winter and spring swells that really have given Lanzarote its Hawaii of Europe renown. Double to triple overhead conditions regularly hit the reefs and many of the spots produce waves of intensely high quality on even the most average of swells. The predominant NE trade winds can be a problem and although this wind is fine for Famara beach and La Derecha in La Santa, it can grow in intensity until all the island is under virtual shutdown. Likewise the Sirocco, a desert wind that comes from the E or S can cause havoc to the surf and the island too, but its worth noting that there are times during the Sirocco when a number of north coast breaks like El Quemao can be at their finest. East coast breaks are inconsistent and often cross/onshore in the NE/E winds but occasionally show form when the winds back off. Jameos del Agua is rideable in NE winds and is also the longest wave on Lanzarote.
The surf is consistent throughout most of the year with pretty much constant swell from September to May. The optimum months from October to April are most likely to have lighter, offshore winds. When the Atlantic summer flat spells arrive, then surprisingly, the northwestern and northeastern breaks of Lanzarote can receive waves from the constant NE trade winds.