Better late than never!

Note, I am using the latest version of the game, and playing on Master Mode:
(Ver. 1.6.0 / DLC Ver. 3.0.0, April 25, 2019)

I do not know if either of those details matter, but this has worked fairly consistently for me when Farosh (Thunder/Lightning Dragon) does not spawn at 5AM in Riola Spring / Lake Floria.

Let me know if this works for you!

#botw #zelda #breathofthewild