Since you're using Weather-Display, the data is likely from clientraw.txt for the wx graphic.
Change wxgraphic.php from (float)$gust = round("$data[2]",$wind_prec);
to (float)$gust = round("$data[71]",$wind_prec);
to pick up the max gust for today from clientraw.txt which is field 71 (starting from the count of 0)
Best regards,
Ken