Menorca is north from Ibiza and I have never been there. We get swarms of jellyfish in the really hot weather which I suppose would be July so ask around to be safe as they can really hurt. Some of our beaches are rendered useless as they literally glisten with jellyfish and it is madness to walk amongst them. If you do get stung put vinegar on it. I have given up swimming in the sea because of the jellyfish, but Spanish kids love hauling them out of the water and putting into buckets so maybe I overreact.