We have loved Barcelona in May and in late Sept, but it would likely be too hot in July. Would definitely say No to Venice. Son went with a youth music trip and found it dreadfully hot (90s… hmmm, maybe unusual summer?)/humid… he and pals mostly sought out places to chill in AC. We returned as a family in May and all really loved that experience.
Per weather research, I highly recommend WEATHERSPARK. Posted link is example, using Venice. Venice Climate, Weather By Month, Average Temperature (Italy) - Weather Spark
If you scroll through you’ll see many different helpful graphs. My favorite annual composite (still using Venice example)
