Google announced on Google+ that Google Analytics will now will automatically convert your AdWords cost, CPC and ROAS figures to the currency you are using in your Google AdWords account.
Google said, "to make it easier to compare your AdWords cost data with your other data in Google Analytics, we recently enabled currency conversion from AdWords to GA."
This will specifically impact your metrics for "Cost", "CPC" and "ROAS" in Google Analytics, if your linked AdWords account uses a difference currency.
The exchange rate used is the exchange rate at the midpoint of the reporting time range.
Forum discussion at Google+.
