To achieve sun protection, Patagonia takes a varied approach, depending on the degree of protection desired and the fabric used. Elements of the strategy can range from yarn selection to fabric construction to the use of special finishes (especially for light colors which generally provide less protection).
UPF stands for “Ultraviolet Protection Factor.” This value represents the fractional amount of the sun’s harmful UV rays that pass through a fabric. A rating of “25” indicates that only 1/25th , or 4% of the UV rays pass through the garment. The higher the UPF rating, the lower the amount of UV rays that reach your skin.
Patagonia products with rated UPF protection are tested independently to meet Australia/New Zealand or AATCC protocols. A rating of 15-24 earns a product a rating of “good”; a rating of 25-39 is "very good"; and a rating of 40-50+ is “excellent.” *
* When tested in accordance with Australian/New Zealand test methods AS/NZS 4399 or AATCC 183/AS