It is the shortest day of the year, and crowds will gather for sun-up at Newgrange in Co Meath to mark the event.
The Winter Solstice can be experienced at the prehistoric monument for several days around today (December 21), but today is the big-ticket event with those lucky enough to attend having sometimes waited for years for the opportunity.
Sunrise is expected at 8.45am.
The solstice will be streamed live on the RTE News Now Channel from 8.55am.
The Winter Solstice illumination at Newgrange was first was streamed live on the internet in 2007. Victor Reijs posted a six-minute compilation on YouTube of the one hour OPW (Office of Public Works) streamed video.