Most of Europe has nice weather this time of the year, maybe except UK
As for beaches and casinos: Malta, Southern Coast of Spain, possibly also Majorca / Ibiza. They all have casinos but I don't know the current state of their poker offerings especially for the latter, but I think they had some.
If you want something with sure action Malta or Barcelona. Amsterdam usually has nice weather this time of the year too and is close to beaches
edit says San remo prolly fits your criteria too