Vortex crystals are ordered vortex structures resulting from complex interactions in dynamical systems. Widely known to form in rotating superfluids, they were long thought to have no classical counterpart. However, recent observations of similar patterns in Jupiter’s polar atmosphere suggest their existence in classical flows as well. This study investigates the spontaneous emergence of vortex crystals in rotating classical flows, an intriguing example of self-organization in nonlinear systems. Direct numerical simulations of the Navier-Stokes equation in a rotating frame show the spontaneous emergence of out-of-equilibrium, transitory vortex crystals. These structures, resembling hexagonal lattices, are analogous to pattern formation observed in other complex systems. The evolution of energy spectra and vortex morphology over time is analyzed, and statistical measures are applied to characterize the space-time dynamics. Notably, enclosures with aspect ratios resembling hexagonal lattice symmetries were explored to assess their influence on the regularity and stability of vortex patterns. Voronöi tessellation analysis is used to quantify the regularity of vortex configurations and its correlation with the longevity of the crystals. Finally, the study reveals a power law connecting the system’s rotational intensity with the periodicity of the vortex lattice, and the existence of a critical value in the control parameter, suggesting a dynamic akin to phase transitions, and offering fresh insights into pattern formation and self-organization in turbulent flows.