The wind does not change that much during a normal flight.
Not necessarily true! I landed a couple of hours ago on Runway 06, with a northerly wind. Snow is now blowing left to right past my window, suggesting a strong westerly has very quickly developed.
TAF is EGMC 281510Z 281601 32012KT 9999 BKN020 PROB30 TEMPO 1618 33015G27KT 4000 SHRASN BKN014