The only reliable way to know the winds aloft with sufficient accuracy (given the relatively low tolerance of small UAVs to wind) is either briefly to put the aircraft into ATTI mode at the altitude in question and observed its drift velocity direction and speed (not possible with the Mavic unless you have modified system parameters to allow that), or to fly it briefly in the direction of interest for the flight away from you, then reverse it and fly back, and observe the difference in speed achieved. Also don't ignore high-wind warnings such as the one that you were given at 166 seconds when you reached 1200 ft.
Also, in terms of general piloting and informed decisions, perhaps consider not flying around at over 1200 ft AGL after being notified that you are flying in Tofino surface - 3100 ft MSL Class E controlled airspace.
