Friday, June 21, 2013

Peak Of Light Hits With First Day Of Summer

Today's the first day of summer, which means the longest amount of daylight and the highest sun angles north of the Tropic of Cancer in the Northern Hemisphere. From here through December 21st, it's all downhill in terms of daylight length, sun angle, and then eventually temperatures.

Our sunrise today was at 5:32 AM and will gradually nudge later each day for the next several months.  By four months from today, sunrises will be after 7 AM across the region and we'll quickly be dwindling under eleven hours of daylight.  Today's daylight totals just over fifteen.

In other cities throughout the country, that trend also takes place -- daylight lengths gradually will shorten and sunrises will become later and later over the next several months. It's more notable across the northern parts of the country than it is down in New Orleans or Miami, but notable regardless as much of the country shaves off varying amounts of daylight from here on out.

In the tropical parts of the hemisphere (below 23.5 degrees latitude), the highest sun angles actually occur on two different days, thanks to the our axial tilt on Earth nudging the sun's direct rays higher and lower in the sky through the year and the sun is on its "journey" towards or away from its highest most latitude, which would occur today when the direct rays from the sun reach the Tropic of Cancer.  In San Juan, for instance, today brings the longest amounts of daylight (13 hours, 14 minutes) but the highest sun angle occurs on both May 13th and July 29th as the sun is directly overhead on both days.  Regardless of where the sun's direct rays are, today is still the longest daylight period in San Juan.