Your trees have peach leaf curl Twinyard.
Rain is the "carrier" of spores causing this and, yes, it will (if bad enough) defoliate your trees....fruit drop will result.
Peach leaf curl is esp harmful at bud burst and on new growth. The rain washes the spores onto the non resistant new leaves.
Fan trained bushes against a wall or fence with a polythene sheet fixed above them to roll down when wet will resolve this problem. Or bushes of a manageable size can be protected with an "umbrella" of polythene. Or grown in a greenhouse.
Copper sprays at leaf drop and again at bud burst are effective but have to be re applied after rain.
Or grow a PLC resostant variety like Avalon.
I have 2 peaches in large pots.....currently PLC free with peaches swelling......that were kept in the gh until a couple of weeks ago. They are now outside but the foliage is pretty well resistant now it has grown out of its juvenile stage.
So, Twinyard, its a question of size......can you spray or protect your bushes or are they too big?