I been living in Altep using a sync down to 44 (with other account job), and whenever I'm online, Earth weather is never present most of the time, and when it is, its Earthsday, then I have to wait 3 or 4 game days before it shows up again even if the weather linkshell predicts it for 3 or 4 straight game days.
I only seen double earth weather one time during the last 3 trials I spent in Altep. I'm probably going to move to Eldime or Garliage for the trial with the undead. . .