The flagship measurement of the JUNO experiment is the determination of the neutrino mass ordering. Here we revisit its prospects to make this determination by 2030, using the current global knowledge of the relevant neutrino parameters as well as current information on the reactor configuration and the critical parameters of the JUNO detector. We pay particular attention to the nonlinear detector energy response. Using the measurement of θ13 from Daya Bay, but without information from other experiments, we estimate the probability of JUNO determining the neutrino mass ordering at ≥3σ to be 31% by 2030. As this probability is particularly sensitive to the true values of the oscillation parameters, especially Δm212, JUNO's improved measurements of sin2θ12, Δm212 and |Δmee2|, obtained after a couple of years of operation, will allow an updated estimate of the probability that JUNO alone can determine the neutrino mass ordering by the end of the decade. Combining JUNO's measurement of |Δmee2| with other experiments in a global fit will most likely lead to an earlier determination of the mass ordering. © 2021 authors. Published by the American Physical Society.