Where in early May is the warmest place to visit in Europe?
Probably the desert near Almeria in Spain?
Well south is good bet,, thinking Rome, Athens, Istanbul , but its weather, who knows what you will really end up with,, have you just thought about where you want to go and just looked at weather charts? How warm do you want,, like beach weather?
Or Malta and/or Sicily. . .
Rome, Capri and the Amalfi Coast was perfect for touring (but not swimming weather) in early May last year......but, like here at home....some years our weather in Nashville is perfect in early May and some years it is really chilly and rainy. Expect evenings to be a bit chilly that time of year, but we also had chilly evenings in Tuscany in August one year.......weather varies.