Contour Plot Date/Depth/Temperature

I am trying to create a Contour Plot containing the values: Date/Waterdepth/Temperature. The table looks like that in Excel, were blue=depth, orange=dates and green=temperature:

Here is my code and the error I receive:

data = readtable('temperatur.xls','Range','A1:H21');
x = data(2:end,1);
y = data(1,2:end);
z = data(2:end,2:end);
contourf(x, y, z);

It appears to me that Matlab has an issue with the date-time format. I have tried to use numerous different date formats but could not get it to work. The XLS file is attached to this question. Any help is very much appreciated!

[Dennis Mayk]

Okay, so I figured out how to solve this and just want to share it here if somebody else faces the same problem. The the problem seemed to be the formatting of my excel dates: DD.MM.YYYY when I changed these to the format MM.DD.YYYY I could use the datenum(t) function to transfer the dates to matlab dates and contourf worked like a charm.

[Ruben]

Hello, I am trying to do the exact same thing however my datetime values are in MM/DD/YY HH:MM:SS since I have data for every 5 minutes. I get the same exact issues, except datenum just fails outright. Any suggestions?