2025 Summer Equinox. The equinox in the northern hemisphere occurs twice a year around 20 march (the spring equinox) and around 22 september (the autumn equinox). Equinox means equal day and night (12 hours each).

The summer solstice occurs once a year in december when the sun’s track across the australian sky reaches its highest point. The september equinox occurs at 18:17 utc.