How to plot time-series data with hourly intervals on x-axis?

Q&A
2

Maybe see (21) Time-series of RedHat stock price — GMT 6.5.0 documentation and 4. Standardized command line options — GMT 6.5.0 documentation.

Does gmt set FORMAT_CLOCK_MAP hh:mm and -Bxa6Hf6h do what you want? (Not tested)