Top panel: Turbulent velocity values measured in the warm or cold phase by Gaspari et al. (2018, blue points) and Olivares et al. (2019, orange points). The reference dotted line σ ∝ T^1/3 corresponds to Eq. (9), with the cyan-shaded area showing the 1σ uncertainty. The solid lined corresponds to the constant average value given by Eq. (8), with the orange-shaded area showing its 1σ uncertainty. Bottom panel: the histogram distribution of the clusters with σ_v measurement (blue) and of the complementary subsample (green).