July marks the start of the great holiday exodus in Europe. In continental Europe, the great getaway happens around the 15th, while in the UK it starts a week later. Southern Europe is beginning to roast in July, and most of the traffic is to the seaside. So you'll want to be close to water in July - or perhaps in some cool mountain air.
There is alot of choice in July, and sunny beaches are just a few hours away, ideal for families with children. From the Costa Brava to the Amalfi Coast, from Dalaman in Turkey to Biarritz in France, the only unknown will be whether you can get a room. July is a good time to think of finding an island, to temper the hot weather with some cooling island breezes. At the budget end, consider Cyprus or Tenerife, and for something a bit more cultural, Crete has alot to offer. In fact all the Greek islands are worth researching, especialy delightful Paxos, trendy Mykonos and historic Rhodes. Closer to home, the Scilly Isles are lovely in July.
While Europe in hot, it's near southern neighbours are sweltering in July, so this is the one time when Long Haul means very long haul - you would not want to spend long in Dubai, for example, in temperatures over 40 degrees, where it's even too hot to swim in the sea.
Indonesia, and Bali in particular. misses most of the monsoon weather sweeping Asia in July, and parts of Sri Lanka can be good too. But for more relaible weather head for East Africa - Kenya and Tanzania - Brazil, where the rains have moved north, and Canada, whose vast natural landscapes are spectacular in July.
Finally, for something you may not have thought of - the Alps are not just for skiing. Switzerland and Austria are spectacular for mountain walking in July. Flowers will still be in bloom and the views will be spectacular and devoid of heat haze. Alternatively, take a trip to Dubrovnik. The Croatian coast is one of the less well trodden jewels of Europe, and Dubrovnik provides a welcome dose of historic culture.