Morella umbrella attachment makes pretty good sense. Raining doesn’t mean I have to forego my coffee, or get both hands full. Morella adds cup holders to the umbrella so you could set your coffee safely and use the free hand to use the phone, or just say hello to someone.
Holders are attached through a pivot mechanism so your drink stays upright and can allow some free movement of your umbrella hand. And when its not raining, your umbrella still functions as a cup holder. Morella is currently up for funding on Kickstarter.