I agree with you but let’s see why you get this result from your weather file.
Let’s start from a city that we know is sunny. Say Dubai. Here is what radiation rose and values for Dubai looks like:
The values from weather file shows that the hourly direct normal irradiance values (red) are higher than diffuse horizontal irradiance during the most of the year. The radiation rose also shows that direct contribution is higher than diffuse. This is what we expected to happen.
Now let’s move to another city which we know is cloudy for most of the time. What about London?
As expected the sky is more diffuse. You can see the irradiance is changes during the year and is lower in winter versus summer unlike Dubai which was mostly the same during the year. Radiation-rose also matches the values.
So now let’s try your weather file for Shiraz:
Can you see how the data from weather file does not make any sense? Here is why you get more diffuse radiation than direct. I hope this clarifies the issue.
Yes.