Angular velocity of the convective envelope (solid lines) and of the radiative core (dashed lines) shown as a function of time between 1 Myr and 10 Gyr for slow (red), median (green), and fast (blue) rotator models in three mass bins centred on 0.5 M_⊙ (bottom panel), 0.8 M_⊙ (upper right panel) and 1 M_⊙ (upper left panel). The left vertical axis is labelled with angular velocity normalised to the Sun’s, while the right vertical axis is labelled with rotational periods (days). The red, green, and blue tilted squares and associated error bars represent the 25th, 50th, and 90th percentiles of the observed rotational distributions at each sampled age. The black rectangle labelled OD (lower right corner of each panel) shows the angular velocity dispersion of old disk field stars. The open circle is the angular velocity of the present Sun shown for reference, and the dashed black line illustrates Skumanich’s (1972) relationship, Ω ∝ t^{− 1/2}.