Most races and organized rides are held "rain or shine".

My tips for road-riding in the rain:

Watch out for paint and metal (e.g. manhole covers, center lines) as these surfaces become very slippery when wet.

Tap your brakes from time to time to clear the gunk off of the rim. Otherwise your brakes may not "be there" when you need them.

Always carry armwarmers and a vest if the weather looks "iffy". 60F and wet can be pretty darn miserable when riding.

Clear (or yellow) lenses will give you the best visibility, but be prepared to ditch them if they become useless.

Make sure you practice your wet-weather riding on group training rides before you race. A race is not the time to learn new bike skills.

Have towels (one for you and one for the bike) at the finish. Change out of those wet cycling duds ASAP.