Plor problem with windquiver

Hello all,

I tried to use the wind quiver function to plot the wind direction and density for each day during a period of 7 months. However, the graph looks wrong to me. Indeed, instead of showing the wind direction and speed for each day, it plotted the first of each month together, then the second of each month together... until the 31st of each month. Does anybody ahve an idea on how i can solve this problem, please? (find the code i wrote beneath)

Than kyou very much by advance

Jonathan

load wind_dir_str.txt

i=[];
i=find(diff(wind_dir_str(:,1))>0);
date = wind_dir_str(i,1);
spd = wind_dir_str(i,2);
dir = wind_dir_str(i,3);

east=spd.*sin(pi*(dir+180)/180);
north=spd.*cos(pi*(dir+180)/180);

windquiver(date,east,north);