My tent is paler after a lot of time in the sun, what happened?
Our fabrics are very strong and both waterproof and highly water-repellent. However, sun, wind, rain and wear will weaken any fabric over time. A faded or bleached look to the fabric is a sign that the fabric has started to become UV damaged. Just as UV rays from direct sunlight have adverse effects on our skin, the same is true for all materials, including, unfortunately, tent fabrics. Exposure to the sun's rays, especially at altitude and in the southern hemisphere, can weaken a fabric's performance over time.
Perhaps the biggest effect is on tear strength. Extended exposure to UV diminishes any fabric’s tear strength, and this is one of the main reasons we use such high tear strength fabrics.
Another effect of extended UV exposure is diminished water repellency, so that water no longer runs off the fabric as it did when it was new. This does not, however, indicate a reduction in how waterproof the fabric is. Retreating the fabric will improve both protection against UV damage and water repellency, but will not help with tear strength. Read more about how to retreat your tent here.
The best way to deal with UV damage is to minimize it as much as possible. This can be done by pitching your tent in the shade, putting a tarp over it, and not leaving it set up during the day when you don’t need it. This is especially important is high UV environments such as high altitude, glaciers, and deserts.