Well I ride in the rain and I have both yellow and blue jackets.

I also drive in the rain, as I live in Vancouver.

As a driver, I find yellow more visible and unambiguous.

As a cyclist, I know that drivers who don't look for me don't see me, whatever I wear. The day I was hit (by a very slow car - thankfully - that "blew" a red light) I was wearing the yellow kit that makes me look like Big Bird. Makes you wonder.