For a backpacker, an umbrella can be a useful piece of gear to help keep you dry, especially on the desert portions of the PCT and CDT (or any other hike below treeline where it may rain). It is also handy for keeping you shielded from the sun during your hikes. However, be careful with the umbrella if you are hiking in windy conditions as they can get blown around easily.
There are a few different styles of umbrellas designed specifically for backpacking. Most of these are a bit more compact than the full-sized umbrellas that you might use on a daily basis, and they usually weigh less than one pound. They also tend to have a much more sturdy frame than a regular outdoor umbrella.
Some backpack umbrellas come with a pouch that can be attached to your pack to hold it while you are on the trail. This can be a convenient way to keep your umbrella out of the way while you are packing and unpacking your backpack. Others have a strap that you can clip to the top of your backpack for hands-free use.
A backpack umbrella can be an essential piece of gear for thru-hikers. It is especially useful on the desert portions of the PCT and the CDT’s New Mexico and Arizona sections. It can even help to provide shade from the sun and allow you to dress for the temperature rather than for the weather.