User blog comment:ChishioKunrin/RWBY 3 Livestream points/@comment-1430834-20160213062145/@comment-4010415-20160213070133

Personally, I think the time span between the Black Trailer and Heroes and Monsters is at least a year.

The Black Trailer may have happened months before the very first episode of RWBY, but Heroes and Monsters takes place almost a year after the first episode of the series.