Abstract: The Cassie−Wenzel(C−W) wetting transition on superhydrophobic surfaces has been extensively explored. However, the influence of environmental humidity on wettability transformation of irregular surfaces formed by film mulch is not sufficiently explored. The static contact angle change of water droplets induced by different temperatures and ambient humidity was studied by ground cold environment test. The results show that low temperature induces the drop contact angle to decrease, and the surface condensation occurs. After the temperature is stabilized, humidity becomes the main factor affecting the change of the contact angle. The freezing delay time and the contact angle before freezing are affected by the temperature. The effects of temperature and humidity on the contact angle can be quantitatively evaluated by the low temperature and freezing test of water droplets. The contact angle decreases by 5.0° ± 1.7° for every 5 ℃ decrease in temperature. When the temperature is stabilized, the contact angle of water droplets decreases by 2.4° ± 0.7° per minute at a relative humidity of 88% and by 0.9° ± 0.2° per minute at a relative humidity of 45%.