My first ’s a sum of money that I have never seen

My first ’s a sum of money that I have never seen Though I have earned it often and spent it too, I ween.

When money is my second ’t is often hard to get; My second is a pretty sight, although it ’s rather wet.

My whole ’s a sad misfortune caused by a summer rain; It makes much trouble in my first, and goes against the grain.