It can be difficult or impossible for an HSPer to manage a cane, walker, wheel chair or scooter AND an umbrella. Here are some different products that can give you hands-free umbrella coverage to protect from rain or provide shade on a sunny day.
Umbrella holder for wheelchair
Brella Bag
BagBoy umbrella holder
http://www.bagboycompany.com/p-39-umbrella-holder.aspx
These products might also be available on Amazon.com, Ebay or in local stores.