Summer solstice: the longest day of the year (north side)

 Summer solstice - Wikipedia

"The summer solstice, also called the estival solstice^[7] or midsummer, occurs when one of Earth's poles has its maximum tilt toward the Sun.

It happens twice yearly, once in each hemisphere (Northern and Southern).
For that hemisphere, the summer solstice is the day with the longest period of daylight and shortest night of the year, when the Sun is at its highest position in the sky.

At either pole there is continuous daylight at the time of its summer solstice.
The opposite event is the winter solstice."

The midnight sun | Where the sun never sets

"Svalbard is the place in Norway where the midnight sun occurs for the longest period.
Here, the sun doesn’t set between 20 April and 22 August."