The water is perfectly safe to drink in Rhodes, but people still prefer to buy bottled to be on the safe side. Remember the ice cubes are bought in at many bars, so is more than likely the same as the bottled water. As you can see from the charts above it's gonna be pretty hot. The sun in can be relentless in Lindos, but there's always a friendly bar to shelter in. Walking the streets can be surprisingly cool as they are narrow and very shaded. Avoid them from 11-5 as this is when they are invaded with the outside tourists.