Inline skates have PU (polyurethane) wheels which have no traction on wet surfaces. The large wheel on Chariot Skates, however, has a normal pneumatic rubber bicycle tire that will grip the road in the wet.
I (the inventor) have been skating on Chariot Skates a few times in the wet and rain and find it to be good training. The rear wheels are PU (like inline skates) and will slide in the wet, so I need to make sure I push with the balls of my feet & the large wheel rather than with my heels & the rear wheels. This is the best technique for wheel-skating so, although I need to be more careful in the wet, I enjoy the opportunity to improve my technique. Chariot Skates would not be much fun in heavy rain but I have never let a bit of rain stop me; I have gone out for several hours in which time I’ll travel 40 or 50 kilometers. If it starts raining I just keep going!