We theoretically study the emission statistics of a weakly nonlinear photonic dimer during coherent oscillations. We show that the phase and population dynamics allow to periodically meet an optimal squeezing condition resulting in a strongly nonclassical emission statistics. By considering an exciton-polariton Josephson junction driven resonantly by a pulsed classical source, we show that a sizable antibunching should emerge in such a semiconductor system where intrinsic nonclassical signatures have remained elusive to date.