How do I average hourly daily velocity data and plot the answer?

I am very new to matlab. I have hourly daily wind velocity data for five years, for two months. I need to average these five years for each hour of the day for each month separately, and then plot the average wind speed for months by hour on the same graph. The y=speed and the x=hour of the day (0-23). My data are in an array such that column 2 is the month, column 3 is the day, column 4 is hour and column 7 is the wind speed. I know this is possible but I'm struggling with an efficient/elegant way to do so. Thanks!

[Cedric]

What have you done so far?

Look at e.g. ACCUMARRAY and/or SPLITAPPLY and train with a simple example so you understand how that works.

[geog170]

Thanks Cedric, I tried accumarray and that was the solution.