Mercury conjuncts Pluto December 19, then squares Uranus December 20, and this will be an obsessive transit, prone to change and unexpected news.
While this will affect those with cardinal planets (Cancer, Aries, Libra and Capricorn) at 13-17 degrees, this will color the energy for all of us, and in the world.
Mercury-Pluto is intense, and at times can border on obsessive energy. While it is good for getting to the bottom of something, there are times it is hard to let an idea or thought go with this transit. It can be argument prone, or you could try and convince someone of something, or vice versa. It can be heavy and overly intense energy.
You should use caution while driving or traveling, and my advice is to try and avoid arguments at this time. As Mercury rules the mind and thinking you could change your mind about something or reach an epiphany.
From here Mercury squares Uranus and this is a nervous energy prone to changeability and changes in plans or unexpected news. Impractical ideas can occur, a tendency to jump to conclusions without facts, communication breakdowns (be careful when you hit SEND) mental vacillation, worry, and unexpected situations involving neighbors, friends or co-workers. Endings or a change in thinking can occur.
As this sets off the Uranus-Pluto square events can be large for some.
This transit will play out on the world stage. Mercury rules young people, communication, travel and speech. We could hear about events (in the US) that disrupt security, unexpected events and situations that involve young people or transportation, and it will be a volatile time, yet again. Events will likely play out before the transit is exact.