Due to the expansion of the league to 12 teams through the inclusion of two Italian clubs this season, competitive league matches are being played during the RBS 6 Nations period.
The Magners League has already experimented with Thursday night rugby this season when the Cardiff Blues hosted Connacht on September 30. That game, screened live on RTE and BBC Wales, attracted a crowd of 11,058.
Celtic Rugby tournament director David Jordan said: "Due to the expansion of our league, we have had to schedule fixtures during the international windows.
"his means that in the New Year, matches in rounds 13 to 18 will overlap with two of the RBS 6 Nations weekends.
"We have endeavoured to avoid clashing with international matches at several levels (senior, 'A' and Under-20) and Thursday night fixtures have been selected for some teams during the additional rounds that take place over those Six Nations weekends.
"Details for the matches to be played in rounds 19 to 21 will be announced in early March. It is planned for there to be simultaneous kick-offs for all games in the final round over the weekend of May 6-8."
Round 13 includes a repeat of last season's inaugural Magners League grand final when the reigning champions, the Ospreys, travel to the RDS to face a Leinster side they recently pipped 19-15 on home soil to move into the play-off Zone. That game in Dublin is on Friday, January 7 (live on TG4 at 7.35pm).
Connacht will once again feature in a Thursday night game in Wales when they travel to face the Newport Gwent Dragons at Rodney Parade on January 6 (live on S4C at 7.35pm).
In round 14, the Italian newcomers Aironi Rugby will travel to Dublin to face Leinster at the RDS on Thursday, February 10 (live on RTE at 7.05pm).
The Scarlets will face Edinburgh at Parc y Scarlets on Thursday, February 24 (live on S4C at 7.35pm) to kick off round 16.
The Magners League's extensive broadcast platform means that at this stage, no fewer than 29 of the 36 fixtures in rounds 13-18 will be broadcast live.
Click here for the full Magners League fixtures list.