Firebase is a 360 analytics tool to track user behaviour across multiple platforms (WEB – WAP – PWA – APP – Native, Hybrid). While 
extracting the hourly report, what time you get GMT or Local time?
Solution:
It depends on from where you extract the data… are you extracting the data from firebase or bigquery or datastudio…
If you extract the data from firebase or bigquery, you get the firebase zone setting time
If you extract the data from datastudio, you get the GMT Setting time
So, it depends on from where you extract the data. 
