> Typically pretty wet weather for the (spring) race

Paris–Roubaix is certainly memorable when it's wet and muddy, but the last time it happened was in 2002! Early spring is the driest part of the year in north-eastern France, and so the usual conditions for the race are dry and dusty. See the Inner Ring: https://inrng.com/2016/04/rain-for-roubaix/