When I see that there's a fair chance of rain the week before a race, I get excited. I know that the majority of the other racers are already feeling, if not defeated, then at least nervous. It also keeps the fairweather riders away and helps to ensure an experienced peloton.
Rain does bring some added dangers, but for the most part I believe it is like riding on dry roads.
INCREASED DANGERS FROM RAIN
- Corners with slick paint or manhole covers.
- Reduced visibility.
- Nervous racers.
- Brakes don't work as well.
For visibility, I generally wear my glasses and simply deal with reduced visibility. Riding without glasses is better, but with all the water kicking up from the road, and especially when the wind blows the wind in your face, it's more difficult to see and if the wind is strong enough it can be painful.
Braking is an issue, but during a race you don't really want to break anyway, and when it's raining the peloton naturally goes through corners a bit slower than usual.
ATTACKING IN THE RAIN
When it starts coming down, that can be a good time to attack and test the peloton. Some racers will simply fall away. It's also important to pay attention for the attacks that will come, and avoid being in the wrong half of the peloton when it splits by someone being caught off guard or unable to hold on, and because of reduced visibility no one sees it happening.
Rain, like in a dry race, is only dangerous if people are not paying attention, or if they allow themselves to be distracted by it. If you stay alert you'll be pretty okay. If you start overthinking the rain, you'll lose sight of the race.