A leap second is a one-second adjustment that is occasionally applied to Coordinated Universal Time (UTC) in order to keep its time of day close to the mean solar time. Without this correction, time reckoned by Earth's rotation drifts away from atomic time because of irregularities in the Earth's rate of rotation. Since this system of correction was implemented in 1972, 25 such leap seconds have been inserted. The most recent one happened on June 30, 2012 at 23:59:60 UTC. A leap second will again be inserted at the end of June 30, 2015 at 23:59:60 UTC. Earth's rotation is quite unpredictable in the long term, which explains why leap seconds are announced only six months in advance.
Starbucks has agreed to let us use their Wi-Fi to watch the event unfold in real time on www.time.gov. Here's an opportunity to celebrate a relatively rare event with your geocaching friends. You can also consider this as preparation for Leap Day celebrations on February 29, 2016.
Location: Starbucks Coffee, Huntsman Square, 7475 Huntsman Blvd, Springfield, VA 22153
Date: Tuesday, June 30, 2015
Time: 7:30pm until 8:15pm. The actual leap second occurs at 7:59:60 pm local time, so plan on being there in time for the big event.