When one of the Earth’s poles reaches its maximum tilt toward the sun, it is known as the summer solstice. The sun takes the longest route through the sky on this date, resulting in more daylight than any other day of the year. The summer solstice, though we’ve been enjoying lighter evenings for a while, is the official start of the astronomical summer.

After that, the days will gradually get shorter, with the autumn equinox in September 2021 signaling the end of summer. For those residing north of the Equator, June 21 will be the longest day of the year in 2021. This day is known as the summer solstice, as it is the longest day of the summer season. When the sun lies directly over the Tropic of Cancer, or right over 23.5 degrees north latitude, it causes this phenomenon.

On June 21 Monday, at 9:02 a.m., this will occur (Indian Standard Time).
Because the Earth revolves on its axis, the Northern Hemisphere receives more direct sunshine throughout a day between March and September, resulting in summer for Northern Hemisphere residents. The Southern Hemisphere receives more sunlight for the rest of the year.

The Earth’s axis around which the planet rotates once every day is tilted. So that the North Pole faces the sun and the South Pole faces away from it. This imaginary axis runs from top to bottom across the middle of the Earth and remains slanted at 23.5 degrees about the sun.

As a result, the solstice as defined by NASA is the moment in time when the North Pole faces the sun more directly than at any other time during the year. In Latin, solstice means “the sun stands still.” The Northern Hemisphere normally receives the most sunlight during this period on June 20, 21, or 22.

The Southern Hemisphere, on the other hand, receives the greatest sunlight on December 21, 22, or 23, the northern hemisphere’s longest night– the winter solstice. Although June 21 will be the longest day of the year in 2021, it does not mean it will have the earliest sunrise or the latest sunset. It changes as a country’s latitudinal location.

The day length in New Delhi is 13:58:01, with sunrise at 5:23 a.m. and sunset at 7:21 p.m. In Mumbai, sunrise will be at 6:02 a.m. and sunset will be at 7:18 p.m., with a shorter day duration of 13:16:20. In Chennai, which is even closer to the equator, sunrise will be at 5:43 a.m., sunset at 6:37 p.m., and day duration will be the shortest among large cities at 12:53:48.