Summer Solstice 2011: Why is the Longest Day of the Year not the Warmest?

 
on June 21 2011 7:38 AM

June 21 is the longest day of the year here in the northern Hemisphere and also marks the official beginning of the summer season.

But, here is an interesting fact about the summer solstice. The longest day of the year is not normally the warmest.

Some of you may be wondering why the longest day of the year is not normally the warmest day of the year. There is a lag between the longest day of the year and the warmest average temperatures in most of the mid and high latitude locations.

The Sun's angle is high before and after the summer solstice with a maximum number of daylight minutes. As the Sun begins to move lower in the sky, the length of daylight decreases, National Weather Service says.

For example, in New Mexico's Albuquerque, the maximum daily temperature occurs nearly 3 weeks later in mid July. This lag in temperature occurs because even though the minutes of daylight are decreasing, Earth's surface and atmosphere continues to receive more energy than just what it receives from the Sun. Average temperatures continue to climb until the Sun drops lower in the sky.

In Albuquerque, July averages 3.7F degrees higher than June, with August also warmer than June by 1.3F, even though the length of days in August is considerably less than the length of days in June.

Depending on the shift of the calendar, the Summer Solstice occurs between December 21 and December 22 each year in the Southern Hemisphere, and between June 20 and June 21 in the Northern Hemisphere.

As a major celestial event, the Solstice happens twice in a year, during summer and winter. The Northern Hemisphere celebrates in June, but the people on the Southern half of the earth have their longest summer day in December.

The Summer Solstice, which is also called as 'midsummer,' would result in the longest day and the shortest night of the year.

On the day of Summer Solstice, the Sun reaches its highest position in the sky and this happens when Earth's North Pole is tilted the most toward the Sun.

The word 'Solstice' comes from the Latin word solstitium, meaning sol (the sun) and stit (standing). The sun's position at noon actually changes very little in the days surrounding the solstice, hence the concept of the sun standing still, National Weather Service says.

The summer solstice occurs at the moment the earth's tilt toward from the sun is at a maximum. Therefore, on the day of the summer solstice, the Sun appears at its highest elevation with a noontime position that changes very little for several days before and after the summer Solstice.

Due to daylight saving time, the Sun is expected to be at its highest point in Los Angeles at 12:55 p.m., rather than at noon. The exact stopping point of the sun will be at 10:16 a.m. Tuesday.

The Summer Solstice occurs when the sun is directly over the Tropic of Cancer, which is located at 23.5° latitude North, and runs through Mexico, the Bahamas, Egypt, Saudi Arabia, India, and southern China.

Worldwide, the event is approached in various manners, but most have held recognition of sign of the fertility, involving holidays, festivals, gatherings, rituals or other celebrations around that time.

Also, Google has put its Google Doodle welcoming the Summer Solstice by putting a floral doodle called the First Day of Summer by Japanese artist Takashi Murakami on its home page.

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