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The dipole is the $\ell =1$ angular component of Cosmic microwave background anisotropy. Its leading observed contribution is a Doppler dipole from observer motion, producing one hotter and one cooler hemisphere. Interpreting the whole measured dipole as motion is a physical model; an intrinsic dipole is a separate contribution.

The stated one-sided temperature contrast is $\beta =0.00105$, so the Doppler dipole givesThe motion is toward the hotter region. The contrast already gives one side relative to the mean; the hot-to-cold difference would be twice as large.