We compute (pseudo)critical temperature, Tc, of chiral symmetry restoration for quark matter in the background of parallel electric and magnetic fields. This field configuration leads to the production of a chiral medium on a time scale τ, characterized by a nonvanishing value of the chiral density that equilibrates due to microscopic processes in the thermal bath. We estimate the relaxation time τ to be about ≈0.1−1 fm/c around the chiral crossover; then we compute the effect of the fields and of the chiral medium at the crossover. We find Tc to be lowered by the external fields in the chiral medium.