The first rain after a dry spell is always slippy due to deposits on the road surface. Regular rain washes these off. Road surfaces are usually a bit grippier in rainy climates, but white paint and metal covers carry usual warnings.
Drivers are used to poor visibility, but it helps to use lights and hi viz clothing.
Wear gloves/mitts and use modern foam bar tape.
Tyres make a big difference in grip and some are known for being good grippers in cold and wet.