Rain is not necessarily a reason for not flying; but it usually comes with poor visibility, which is.
As already said: flying one hour per month will get you nowhere (been there, tried that).
Be aware that there are more reasons to keep you grounded than the actual weather: after a long period of rain, grass runways tend to be soaked and thus unusable for a week at least. And then finally when the runway is again in use, and the skies are reasonably clear, everybody wants to go up, so no chance to book a club or school plane.
Not to mention a/c broke, a/c planned maintenance, instructor illness or other priorities and what not.
Talk to a few students at your chosen place for learning, and get an idea of how bad these limitations are.
Oh yes, IF you do decide to go for it: clean aircraft. Either wash them outside before your flight, or hoover the inside or whatever, but do show you care for the plane. Your instructor will be delighted to find you at the job - if he's any worth as a pilot.
One more afterthought: before anything else, go for the required medical. 't Would be too bad to spend a good deal of money, time, and effort, only to find there's some teeny medical point that keeps you from being a pilot anyway.