Yay for spring! The warmer weather and longer days have many of us outside for bike rides, BBQs, summer festivals, and countless other outdoor activities. It’s important to remember to use sunscreen, of course, but did you know your clothing can also increase your protection from the sun?All fabrics protect us from those ultraviolet (UV) rays that cause sunburn, wrinkles, and can cause cancer to a certain extent. The clothing that does the best job carries Ultraviolet Protection Factor (UPF) value. Folks that rarely get a sunburn on skin covered by clothing may not need to be concerned with the UPF value of their clothing, but fair skinned people, kids, and people spending extended periods of time in high elevations, near the equator, or around water or snow may benefit from clothing with a high UPF rating.

UPF ratings are similar to SPF ratings that we associate with sunscreens. They range from 15 (good) to 50+ (excellent). There are a variety of factors that contribute to the effectiveness of fabrics blocking the harmful UV rays.

Dense, tight construction - weaves or knits - tend to have higher UPF ratings because there is minimal space between the yarns. Very tightly woven garments with high UPF ratings will use vents to aid air circulation.

The type of dye, not the color of dye that impacts a fabric’s UV transmission. Fabrics engineered for UV protection will have a UPF rating. Without a UPF rating, you can be certain the dye used will not aid UV protection.

Specific chemicals added in the fabric construction can increase it’s effectiveness in protecting UV rays. There are even specialized laundry additives with UV-disrupting compounds that can increase a garment’s UPF rating.

If a garment is stretched 10% or more beyond it’s normal dimension, spaces between the yarns are widened. This can decrease it’s UV protection up to 40%.

A fabrics UV effectiveness can be reduced up to 50% when wet, although the reasoning why is not completely understood.

REI is a great source for UPF apparel. For more information, visit the UPF apparel website.