What type of variation in temperature does the wing undergo?
The temperature rise that is caused by flying at high subsonic/transonic speeds is approximately 40 degrees Celsius. But this happens only at the stagnation point (near the leading edge). Ref: aerodynamics text books.

The A380 and other airliners experience -55 to -60 degrees Celsius during cruise at altitude. Ref: aerodynamics (properties of the atmosphere)

On the ground they may experience up to 60 degrees Celsius of air temperature and with the sun radiation the surface temperature can rise up to approx. 80-90 °C. Depending on color and geographic location on earth. Ref: hard experience :) and Environment control system Analysis.