Evidence for a second finite-temperature transition in Quantum Chromodynamics (QCD) is re-
vealed through the study of centre vortex geometry and its temperature-dependent evolution. Using
the anisotropic dynamical ensembles from the Fastsum collaboration, we conduct a detailed anal-
ysis at several temperatures above and below the established chiral transition. Visualisations of
the centre vortex structure in temporal and spatial lattice slices demonstrate that vortex percola-
tion persists through the chiral transition and ceases at approximately twice the chiral transition
temperature, $π_π$ . This indicates that confinement is maintained up to $π β 2π_π$ , suggesting a second
transition associated with deconfinement. The loss of percolation, quantified by vortex cluster
extent, provides a clear signal for this transition. Statistical analysis of vortex density and cluster
extent is presented which reveals consistent evidence of two transitions in QCD: the chiral transi-
tion at $π_π$ and the deconfinement transition at $π_π β 2π_π$ . By analysing these, and other quantities,
we obtain a precise determination of the deconfinement temperature, $π_π$ = 321(6) MeV.
