Hatch:

 

Does anyone have any insight into the waterproofness of the M365, I remember a YT video which said basically the battery and electronics compartment was not particularly waterproof but that video may have been a way of justifying the aftermarket covers. 

I wonder if anyone bothers to add silicon along the case gaps for example? 

 

I don't feel particularly good about using one in the rain and thus far have avoided using it entirely when wet. This will change when I will have to rely upon it for commuting entirely.

 

Based on my research the weak point appears to be the power button.  Apart from that they seem pretty bulletproof.  There are some overseas sites offering 3D printed rubber covers that stop water from leaking into the electronics.  I've just ordered one, so I'll report back once it arrives.

Obviously you wouldn't want to submerse the battery pack or charging jack in a puddle, but that's usually avoidable even in heavy rain.  Looking at the Bird version of the M365 it appears identical to stock apart from the power console, and they're left out in the elements (albeit maybe in drier climates than NZ).