Mercury Opposing Retrograde Mars...

starts on February 13 (using a 1 degree orb), is exact on February 13 at 9.25pm, leaves on February 14.  Mercury at 4 degrees and 22 minutes of Aquarius, retrograde Mars at 4 degrees and 22 minutes of Leo.

Combined with the last aspect (Mercury Trine Retrograde Saturn), this aspect suggests a major turning point after barriers to successful communication.  It's as though a roadblock has been removed, now allowing open and free communication and expression, most likely of volatile and passionate themes from the past (retrograde Mars in Leo).

Even though this is likely to be a volatile time, the opposition always suggests a turning point and opportunity to view the themes and relationships represented by the planets involved in a more objective way than usual.

As usual, look to see where this aspect is happening to get a feel for where you are likely to reach a turning point and need honest communication.  Also look to see which houses are ruled by Mercury (ones with Gemini or Virgo on the cusp) and Mars (ones with Aries or Scorpio on them).

If you have personal planets or points in Leo and/or Aquarius then you are likely to be especially sensitive to this transit.