OpenWeatherMap Forecast not working

Example:

You will get up to 8 different values for tomorrow (24/3=8), e.g.

21,22,23,24,21,26,27,28 (which value is the correct one for tomorrow?) You have to calculate the average (=24)

Your max value will be 28, but how will you know?

Then you should use this, like @momo90 mentioned above: