We prove that the set of singular times for weak solutions of the space homogeneous Landau equation with Coulomb potential constructed as in [C. Villani, Arch. Rational Mech. Anal. 143 (1998), 273-307] has Hausdorff dimension at most 1 2 .Proposition 2.5. Let f be a suitable solution to the Landau equation (1) on [0, 1] satisfying (7) for some negligible set N ⊂ (0, 1], some q ∈ ( 6 5 , 2), and some C ′ E > 0.