"Arena and Rated Battleground Season 12 is scheduled to end on Tuesday, March 5. At that point, we will determine who is eligible for the end-of-season rewards, a process that should take approximately one week. It's very important for players who feel that they may be eligible for Arena titles and/or the Malevolent Gladiator's Cloud Serpent to refrain from transferring their characters to another realm or faction until after Season 12 ends. The awarding of Season 12 titles and mounts will occur approximately 2 weeks after the season ends.
At the end of the season, Conquest Points will be converted to Honor Points and any honor above 4000 will be converted to gold at a rate of 35 silver per point. The honor cap will remain at 4000.
All Season 12 items will cost Honor Points (equivalent to their previous Conquest Point cost) when the season ends, with the exception of any items with rating requirements attached. These items will no longer be available for purchase.
The next Arena and Rated Battleground season will begin approximately one week after the current season ends. During the break between seasons, all Rated Battleground and Arena matches will be unavailable. Team and Personal Ratings will be reset when Season 13 begins."
Yup thats correct, giving the fact blizzard made a blue post about "you can keep your valor" and said you will have enough time to cap it , this takes us to the 5th when the season ends. Patch will go live on the 5th but arena/rbg won't be available for the first one