Hold off a bit. Lots of rain is a good thing. While Nitrogen doesn't fixate to soil (P&K do), and would eventually wash away, you only really have to worry about it washing away from winter snow melt and spring rains where you are.
Keep an eye out for premature yellowing of the bottom leaves. They shouldn't start yellowing on their own until they're closer to harvest, and then the yellowing should be dispersed throughout the whole plant. Not just at the bottom.
(healthy yellowing close to harvest - Swazi Landrace)
I'm not that far from you. A few years ago we had no rain for almost 2 months. That was a much bigger problem.
