As this liturgical year wraps up, lets take a look at next year and the College of Cardinals. Currently there are 118 electors among the 218 living cardinals, leaving only 2 open "slots" for new voting age cardinals. Assuming no deaths, that will not change until 28 Feb 2016 when Cardinal Mahony loses his elector status.
Pope Francis has created cardinals twice - both in February - but with only 3 opens slots by the end of next February, it seems highly unlikely that he'll do it again next year.
However, by the end of the year, 10 more electors will age out - leaving 13 total open slots. At the time of the creations in 2014, there were 14 open slots and in 2015 there were 10.
So based on that and looking at the traditional times for such a consistory, I predict that the next consistory to create cardinals will be one held on Christ the King weekend in 2016 (19/20 November).
Now looking past that, in 2017 only 4 electors will age out - the last one in April. If I'm correct in the first prediction, there won't be one held in 2017.
2018 is a different story, with 7 cardinals losing their vote - the last one in June. My guess is there will be another consistory to create cardinals in the Spring of 2018.
Of course, I have no inside knowledge and the creation of cardinals is at the complete discretion of the Holy Father.