We investigate the stochasticity in temperature fluctuations in the cosmic microwave background (CMB) radiation data from the Wilkinson Microwave Anisotropy Probe. We show that the angular fluctuation of the temperature is a Markov process with a Markov angular scale, ΘMarkov = 1.01-0.07+0.09. We characterize the complexity of the CMB fluctuations by means of a Fokker–Planck or Langevin equation and measure the associated Kramers–Moyal coefficients for the fluctuating temperature field T(\hat n) and its increment, \Delta T=T(\hat n_1)-T(\hat n_2) . Through this method we show that temperature fluctuations in the CMB have fat tails compared to a Gaussian distribution.