Louisa Reynolds asks at Foreign Policy if we're seeing a Central American Spring. I feel like this might be the wrong question. From its usage in the Middle East, the use of the term "spring" has come to mean rapid, transformative political change sparked by widespread protests (and sometimes armed rebellion). What I see in Central America is the slow, painstaking process of gradually strengthening domestic political institutions to increase horizontal accountability.
It's also not really accurate to say:
For nine weeks now, Guatemalans have been taking to the streets to demand dramatic change — an unusual sight in Central America, where corruption is the norm.
Corruption may be the norm, but Honduras has seen protests since the 2009 coup so they're not unusual everywhere. Those protests demanded dramatic change but did not achieve it. Even Costa Ricans protest corruption. They are, though, quite a sight in Guatemala, and happening largely for external reasons (i.e. CICIG).
It's hard to see rapid transformation in any Central American country. I'd say the best case scenario is that presidents gradually come to understand that corruption will be prosecuted, that the international community continue to play a constructive role, and that Central American elected officials slowly demonstrate why citizens should trust them.
If Otto Pérez Molina actually resigns or is otherwise democratically removed before his term is over, it'll be historic. But I am not sure it'll mean long-term change, which is a lot harder and requires chipping away at an oligarchy that will not give up easily.