Average hourly values of the same day (one column with six months of data)

[Exorbit]

Hello ,
1)I have on two columns(4000 rows) data that represents hourly values of the temperature and the date and hour when it was taken. I need an average of each 24 values accounting for one day for all the interval.

2)I also need to select every 24th cell of the whole column .

Thank you very much , I hope I was clear enough . I also attached the excel file.
Senzor copac rariste - Copy.xlsx