are some areas more equipped to handle diversity than others?

[freepcrusher]

Like I would say that the Bay Area for instance is better equipped to handle racial and ethnic diversity than the Inland Empire.

[Franknburger]

All over the world, coastal areas and especially major seaports have traditionally been more exposed to external, influences, also experienced more foreign settlement, than inland areas. Compare e.g. Barcelona with Madrid, Hamburg with Munich, Amsterdam with Brussels, St. Petersburg with Moscow, Riga with Vilnius,  Casablanca with Marrakesh, Cape Town with Johannesburg, or Shanghai with Beijing.
 
Major inland trading centres and routes (navigable rivers, mountain passes) seem to come next. Also considerable external exposure and foreign settlement, but typically from less (culturally) distant areas than along the coasts.

What is common to both is the locals' experience that foreigners bring wealth (as trading partners and/or tourists).
Secondly, such places have developed a strong local identity (as opposed to ethnic / national identity), which at the same time helps to quickly integrate foreigners, and strengthens resilience against the "cultural shocks" they may bring. For me personally, the difference between Hannover (which does not have much of a local identity but at best feels Lower Saxon), and the extremely hanseatic Hamburg was striking. Frankfurt and Cologne, both cities with a long-term trading  tradition, are other German examples of strong local identity. On the Mediterranean Sea, Barcelona is obvious, and you, Toni, will probably be able to add a few Italian cases. The US: NYC and San Francisco, of course, probably also Boston, Miami and LA plus a few more.
To come up with more "exotic" examples: The people of Jakarta are proudly referring to themselves as Batavians - a name originally given to them by the Dutch - and at the turn of the millennium, "Dutch retro" bars serving Dutch food were in high fashion. Look at the way how Riga is exhibiting its German, Swedish & Russian heritage, and compare it to the way Vilnius tries to pretend it always was Lithuanian (and never influenced / controlled by Germans / Poles / Russians) ..

On the bottom end of the scale would be rural, peripheral areas. Exposure to outside influences tends to be low. But, more importantly, foreigners have historically in most cases not been a source of wealth, but rather of destruction. Neighbouring tribes stealing cattle or daughters, armies marching through and leaving devastation and burnt fields behind, or a history of conflict with the indigenous population (e.g. a good part of the Western USA).

Cultural domination / takeover by 'foreign' rulers is also not helpful. Some trading centres manage to transcend and integrate this experience into their local identity (the Jakarta/ Riga examples above), but most, and especially the countryside, don't. People have for generations learnt to superficially assimilate to the dominating culture, but underneath preserve their traditional cultural identity. What used to be a virtue of cultural resilience once, may - once the foreign rule has been overcome - turn into the vice of regarding diversity as just another threat of alienation. Aside from many post-colonial third world countries, such patterns are - after centuries of Osman rule - still found across much of the Balkans (I first was made aware of them through, and discussed them intensively with many Bulgarian friends when I worked there). German cultural domination has unfortunately left its mark on many Czech souls (though I feel the country is on a good way of transcending that experience in "Riga style").
Well, and the US South, that I have never visited, may be another example ...