I was thinking of going for 10 days to Iceland but the weather forecast looks like a lot of rain. How bad is the weather right now?

Iceland has just been hit by the remains of Hurricane Cristobal, which a few days ago was drowning people in the Haiti and surrounding areas. It's the kind of wild weather that, at least during summer, you only expect to endure about once every 3 weeks or so, though wild weather does become more common as you get into autumn and winter.
This is the weather forecast site http://en.vedur.is/ showing some rather more normal weather for the next few days at time of writing, indeed reasonably pleasant for the time of year by local standards.
