It's really a matter of (1) how well you dress and (2) personal attitude.

I'm a veteran of many rainy rides but I can tell you that it was more fun when I was younger.   I'm a little more sensitive to the cold and damp weather now at 44 than I was at 25.  I'll ride in pretty steady rain if I have to but draw the line when I hear flood watches, tornado watches, or see lightning strikes.   

I have a riding rain jacket and pants set that has seen many rainy days.    They're good for both cycling and hiking.  I recommend having both.   They are a breathable material yet waterproof (Performance brand).   I stash mine in on the back rack.   Keeping your trunk, arms, and legs dry makes a world of difference especially during cold October rains. 

I'm writing this on Sunday and it looks as though the worst of the rain has stopped.  I hope you didn't hit the downpour this morning.

Good luck!

JoAnn