Cheap flight to warm waters?

Hi all,

I want to use one of the cheap airways (Ryan air etc.) any time over the next 4 weeks to go snorkelling in (hopefully) warm waters somewhere in Europe.

Anyone got any good suggestions?

Ryanair seem to go to a few places on the South Coast of spain for next to nothing.

My (Australian) girlfriend hates the cold so English waters are no good, but will European ones even be warm yet?