Hello Jessie
Your scenario is an interesting one. The two lessons that are closest to your description are the following:
In both of the above lessons, there are two hubs. In the dual hub dual cloud scenario, OSPF is not the best choice, because each spoke has the potential to become a transit router if a downstream link fails. See this post for more details.
In the dual hub single cloud scenario, OSPF is used. Indeed, both hubs are in the same area here and are connected to each other. To answer your specific question, however, it is not unusual to have two hubs in geographically remote locations be in the same OSPF area. This is simply a matter of design.
Take a look at these lessons and let us know if you have any further questions.
I hope this has been helpful!
Laz