Should I drop Italy from my 3-country Euro trip due to October weather?

Hi everyone,

I'm 23 and planning a 5-week trip from September 7 to October 12. I have a Sail Croatia tour week 1, followed by a Contiki Greek Island hopping tour for weeks 2 and 3.

Originally, I planned to spend the final two weeks (Sept 28 - Oct 12) solo travelling in Italy. However, my absolute priority for this trip is a true Mediterranean summer vibe: wearing summer clothes (bikinis, mini skirts), swimming, and hitting beach clubs/partying.

I’m realizing that late September/early October in Italy might be too cold for this, and that beach clubs will likely be closed.

Should I drop Italy and save it for next summer? If I drop it, where should I spend my last two weeks instead to maximize the heat, beach vibes, and hostel party scene for people my age? (Considering Southern Spain or Cyprus?). Or should I even just cut my holiday short to just the two countries Croatia and Greece?

Thanks