This is a challenge cache. This means that it is really hidden at the given coordinates. It also means that you must complete the challenge to be allowed to log the cache. In this case, the challenge is that you must have logged at least one traditional cache on each date - 366 different dates. The logs don't need to be on the same year or on dates immediately after each other, though.
There is a tool at project-gc.com to create an iCal file to put reminders in your calendar on the dates you need to log traditionals to qualify this challenge.