No doubt more changes occurred in mid to late 2013 but winter 2012/2013 was leaning mid 2010s and mostly mid 2010s.
I'm tired of 2012 being seen as detached from 2013 and 2014. 2012 as whole has more in common with 13 and 14 than with late 09-early 2011, despite things that could never exist in 2013-2014 from 2012. Also things that first appeared in 2011 and 2012 became more apparent in 2013 and 2014.
What makes winter 2012-2013 (November 2012 to March 2013) closer to the mid 2010s
Graphic design trends mostly the same/identical to 2013-2014
Big social media awareness and hashtag campaigns as much of a thing
Twitter, facebook and instagram become also more official and widespread personal branding/ or business marketing platform tools like the mid 2010s
The hipster look is 97-99 percent the same with some early 10s styles still in place
Common fashion/hair is 97 percent identical to the mid 2010s
Very particular 2013-2014 looks (13- 2014 hipster undercut and similar hairstyles, massive beards, colorful glasses frames, H&M stretch jeans etc) are already common/increasingly common depending on location
Particular mid 2010s music sounds/styles almost there, there or similar
Many hits are recorded on albums from 2012 and are released as singles in 2013 and 2014
Smart Phones mostly in full swing with some exceptions
Iphones are the go to phone
HD TV mostly there
Streaming/paid streaming becomes more of a thing
In game purchasing is a thing
Topics like LGBT rights mostly respected collectively
Peak of Vice Media
Early SJWs
Wii U and PS Vista
Youtube more in common with mid 2010s at this point