The CRA exam cycle differs among the federal banking regulators, except for "small banks" as defined by the Gramm Leach Bliley Act and the CRA regulation. For small banks last rated Outstanding, the next CRA exam can't start any sooner than 60 months from the end of the last CRA exam. For those rated Satisfactory at the last CRA exam, the next one can't start any sooner than 48 months from the end of the last exam.
One regulator uses those limits as absolutes, and will start both the compliance and CRA exams as soon after the 48 or 60 month periods as possible. Another uses the the premise that the law and reg only say by when you CAN start an exam, not when you must, so they might use that flexibility in their scheduling and not be in a particular hurry to start the next CRA exam.
Beyond that, the exam cycles for large and intermediate small banks are left up to the individual regulatory agencies. Some use a two year cycle. One might use a 3 year or longer cycle, as the CRA is silent on when an exam must be done for these banks. However, the regulators don't like too much time to transpire in between exams if for no other reason than the CRA rating is to be considered during branch and other corporate applications. They don't want to have too stale of a rating.
As for the evaluation period, that will be from the end of the last exam (usually a close date the regulators assign internally) to whenever the examiners decide to cut it off. Some like to deal with whole calendar years. For example, maybe your last CRA exam had an evaluation period that ended 12-31-06. The next evaluation period would generally run from 1-1-07 to 12-31-10 using whole years. Or if they might decide to stretch it to use the most current YTD info you have to offer, maybe something like 6-30-11. AR.