weather data

dear paul
first, i thank you for all your ansewrs and clarifications.
then i have again a question:
I have hourly weather data for 8760 hours but by interval of 30 min. ie I have radiation form 23h30 to 00h30 for the 1st hour and 00h30 to 01h30 for the 2nd and so on.
so when i want to create TMY3 file whith TMY3 file creator i dont knwo how to adjust the data to have a radiation from 00h00 to 01h00. so i use it as they are.
I want to knwo how can i avoid this problem and is this small difference begat big errors on my results.

thank you

Hello,

The impact of using solar radiation data shifted by 30 minutes will depend on the type of system you are modeling and the performance model. I do not know exactly what the impact would be on the results would be.

SAM uses the solar angle at the midpoint of the hour to represent the sun's position over the hour.

Best regards,
Paul.