This was already mentioned before, but I did some math regarding when Doctor Strange would take place, using these two interviews as reference:
http://www.empireonline.com/movies/features/doctor-strange-scott-derrickson/
[video=youtube;pYxmUMCNxCo]https://www.youtube.com/watch?v=pYxmUMCNxCo[/video]
If he recovers for three to six months as said in the former interview, that means that he recovers until some point between May and August 2016 (going from the February 2, 2016 date in Strange's watch before the car crash). Unrealistic of course, but maybe medical technology in the MCU is advanced enough that that could happen.
In the latter interview, at 1:27 in, Mikkelsen says that Strange had trained for nine months by the time he encounters Kaecilius. If that's accurate, that means that the second half of the movie would take at some point between February and May 2017. Since it's snowing in New York in the scene where the Ancient One dies, it's unlikely to take place any later than March.
Working backwards from there, this means that, going from the two interviews, the timeline for the movie would go like this:
-February 2, 2016: Car accident.
-May or June 2016: Strange meets Pangborn, goes to Kathmandu and finds Kamar-Taj, then trains for the next nine months.
-February or March 2017: Strange encounters Kaecilius, then fights and defeats him.
-(?) 2017: Strange meets Thor, events of Thor: Ragnarok.
I know about the closeup on the cracked watch face showing/implying the date of January 2017 when Strange is in Kathmandu, but maybe the car accident screwed up the watch to the point where it stopped telling the accurate time, and he didn't get it fixed?
We may get more concrete info on how long Strange trained for in Ragnarok, Infinity War, or any Doctor Strange sequels though, so I'm just posting this as a possible suggestion until then.