Solstice
What is a solstice?
A solstice marks the longest or shortest day of the year in each hemisphere. Around June, the Northern Hemisphere has its longest day and the Southern Hemisphere its shortest. Around December, they swap.
Longest day, not earliest sunrise
The June solstice has the most daylight in the north, but the earliest sunrise lands about a week before it and the latest sunset about a week after. The two ends of the day do not move in step, because clock noon and Sun noon drift apart through the year — the equation of time. The whole pattern is sitting in the 7-day table on your own town’s sun page if you look at the week around the solstice.
What actually stands still
Watch where the Sun rises for a few weeks and it slides along the horizon, a little further north each morning through northern spring. At the solstice the slide stops, holds for a few days, and heads back the other way. That is the standing-still the name records — not the Sun pausing in the sky, but the turning point of its year.
At the polar circles it is all or nothing
On the June solstice the Sun does not set anywhere inside the Arctic Circle, and does not rise anywhere inside the Antarctic Circle. The polar circles sit at 90° minus 23.4 — the tilt’s other signature. Jump to a solstice on the day/night map and you can see it: the top of the map entirely lit, or entirely dark.
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Why the hottest weeks come later
The most sunlight is not the most heat. Land and ocean keep warming for as long as each day still delivers more energy than its night sheds, so the temperature peak lags the light peak by several weeks — July and August in the north, January and February in the south. The sea lags hardest of all, which is why beach water is warmest long after the longest day has gone.