24 HRS OF DAYLIGHT AND 24 HRS OF DARKNESS: JUNE 21 MYTHS AND MYSTERIES

In astronomy, June 20-21 is an “uncommon” day! On that day, some places receive a full 24 hours of daylight and some receive a full 24 hours of darkness simultaneously; but this phenomenon is no mystery and indeed it happens every year.

However, St. Lucia and its family of equatorial neighbours are exceptions to that astronomical fact. We have never  - and will never - experience 24 hours of daylight nor will we ever experience 24 hours of darkness - just as we will never experience spring, winter and autumn, for the simple reason that we live near the equator. 

 Indeed, June 21 is the longest day of sunlight for places in the Northern Hemisphere; but contrary to what the popular “Eurocentric view” suggests, June 20-21 is not the start of summer (Summer solstice) for “all places” in the Northern Hemisphere; it is the start of summer for “some places” in the Northern Hemisphere.

Secondly, June 20-21 is not the day when the sun rises earliest in the morning nor when it sets latest at night.  The date of earliest sunrise or sunset varies from location to location.  According to meteorologists, the sun rose at 5.37 AM and set 6.33 PM in St. Lucia today.

Why is June 20-21 the longest day of the year?

On or around that time each year, the rays of the sun will be perpendicular to the Tropic of Cancer. And it is on that day the Sun reaches its most northern point in the sky at local noon. After this date, the days start getting shorter.

What therefore happens on June 20-21 is no mystery, no myth: The equator receives twelve hours of daylight, the North Pole and areas north of 66°30' N receive 24 hours of daylight; and the South Pole and areas south of 66°30' S receive 24 hours of darkness