June 21st marks the Summer Solstice and people in the Northern Hemisphere of planet Earth will experience longer daylight than every other day. Since countries like United States, Canada, Russia, Turkmenistan, Azerbaijan fall into the north of the equator, these will experience the longest day of year 2016.

Every year it is not necessary for summer solstice to occur on June 21. This is a usual phenomenon which can take place between June 20 to June 22 every summer.

What is Summer Solstice?

A solstice occurs when the sun is at the highest point in the sky relatively to the equator. This means today Northern Hemisphere is tilted fully towards the sun. And because North Pole is tilted to its extremes towards the sun, Arctic Circle will see 24 hours of daylight.

What makes it the longest day of the year ?

The reason that Summer Solstice makes a day longer is not because it adds few more hours to the already 24 hours cycle, rather it is longer because this day receives the longest hours daylight in the Northern Hemisphere. Those parts of North of the Equator will receive the most sunlight on a Summer Solstice day. (ALSO READ: Monsoon in India: As La Nina replaces El Nino, massive rainfall expected in subcontinent)

SeasonalLagEarthAxis

(image credit: NASA)

Interesting fact

Surprisingly, look up at the moon tonight and you will observe it is a full moon. This will be first time that a moon will appear to be full on a Summer Solstice day since 1948.

Will this also be the hottest day of the year?

To your relief no! Summer solstice will leave earth to receive the maximum energy of sunlight today but would not make it hottest day. The science behind this is Earth doesn’t release the absorbed energy immediately . It absorbs and process and then release the energy later. So, the energy absorbed today will reflect in later part of July or August usually. This phenomenon, according to Weather Works is called Seasonal Temperature Lag. (ALSO READ: According to NASA May 2016 hottest on record)