Just note that dirt on the paint can degrade beading - after a wash, beading can look better than before
As for the incessant rains - not much you can do, really. If you have the time to wash properly, then go ahead; but if not, best to leave the car dirty rather than do a less-than-ideal wash. If you have soft water, you can do a water rinse like jhnkvn does; just blot while drying to ensure you're not dragging dirt. In my case, our water is pretty hard, so I've learned (the hard way) that it's better to just leave the car until I can do a proper wash.