These were exactly my thoughts. It's rare to have rain without wind. Even a mild breeze would distort the shape of the 'umbrella'. Strong winds would require it

These were exactly my thoughts. It's rare to have rain without wind. Even a mild breeze would distort the shape of the 'umbrella'. Strong winds would require it be pointed into the wind as with any umbrella, however without a rigid structure the air curtain would virtually collapse flat providing no protection whatsoever. To work in all weather this umbrella would have to be able to manipulate its output from virtually perpendicular to the shaft to parallel. Honestly, this might work with compressed air, but that itself would present serious problems; you'd likely only be able to charge it once a day and the cylinder would be heavy, but perhaps not as heavy as the original design. It would also enable the umbrella to have a shaft similar in appearance to a regular umbrella.