Do I draw for GTM?

Dry Season is passive, but so is GTM.

Dry Season is constant, not passive. It is always active, from the moment it becomes your revealed plot to the moment it shifts to the used pile.

But even if it was passive, all plot text must be resolved before any passives to revealing plots can be initiated.

So no matter how you slice it, revealing Dry Season will blank GTM before you can initiate the location and draw a card. (i.e., you never get the card.)