When Is The Longest Day 2025. On december 21, 2025 — the longest day of the year in the southern hemisphere — people in sydney, australia, will experience 14 hours, 24 minutes, and 47 seconds of. The midnight sun is a natural phenomenon that occurs in regions near the earth's poles, notably in the arctic and.

On the summer solstice, when the northern tilt is closest to the sun, we have the longest day, usually june 20 or 21. Perihelion is when earth is closest to the sun, happening between january 2 and 4.