Unlike camouflage clothing, the forest doesn't stay the same color year-round. This means that if hunters are really serious about blending in, they have to buy both green and brown camo ... unless, apparently, they're wearing Cabela's new color-changing ColorPhase apparel.
According to Cabela's, "ColorPhase is the world's first camouflage clothing to be printed with rapid-change, temperature-activated dye." This means that when it's warmer outside, in the spring and summer, the fabric is primarily green. As the temperature drops below about 65ºF (18ºC), however, that green starts changing to brown – just like the vegetation does in the fall, although 65º seems a little warm for fall.
And yes, things like body heat, moisture, sunlight and cool winds can indeed also cause it to change color. Remember those Hypercolor T-shirts?
ColorPhase items include caps, gloves, pants, shirts and jackets, ranging in price from US$20 to $80. The color-changing feature is demonstrated in the video below.
Source: Cabela's via Popular Science