According to a U.S. study published in JAMA Dermatology, any fully-functioning handheld umbrella can block more than three-quarters of ultraviolet (UV) light on a sunny day. Black ones do even better, blocking at least 90 percent of rays. ... The sun umbrella blocked more than 99 percent of UV rays.

Are sun umbrellas effective?

Yet they're effective, cheaper and less messy than applying sunscreen. A 2012 study conducted by the Emory Medical School Department of Dermatology found that an umbrella could reduce direct exposure to UV rays by 77% to 99%.

Can you still get sun under an umbrella?

Only shade so deep that you can't see the sky provides total UVB protection, so beach umbrellas don't. ... You can get a noticeable sunburn from sitting under an umbrella in the grass in the middle of the day (sunny or cloudy) after just 35 minutes.