Where in the world is Callie?

My close friend Callie has been traveling around the world working for the University of Virginia's Study at Sea program this semester. I have really enjoyed all the postcards she has sent and the handful of phone calls from around the world. This map shows her route and that today they are between Hawaii and San Diego.

All of the postcards are on display in my apartment:

The postcards from China and Hawaii on the same day. I'm sure they were sent at least a week apart.