Define the formula of Wien law.
WIEN'S LAW:
λm T = constant
Here:
λm = Peak Wavelength (m)
T = Surface Temperature (K)
Constant = 2.898 x 10-3mK
It rearranges to λm = 2.898 x 10-3/ T
Above rearranged equation demonstration why the peak wavelength reduces as temperature increases. It decrease into wavelength describes why objects glow first red, after that orange-red, then yellow, after that even blue. Such colours are successive decreases into wavelength.