June 21 is the longest day of the year for the Northern Hemisphere, which includes Pakistan and India on summer vacation.

It happens when the Earth’s axis is tilted about 23.5 degrees relative to its orbit outside the Sun.

On this day, the North Pole is tilted closest to the Sun, so the Sun reaches its highest point in the sky. This affects the daylight hours in areas in the Northern Hemisphere.

Cities closer to the equator will have slightly shorter daylight hours than those further north.

Traditionally, the weekend marks the longest day and the start of summer.

As the Earth continues to orbit outside the Sun, the days gradually shorten after the summer solstice until the winter months in December, the shortest day of the year.