The key idea here is wether it is day or night. If it is daylight, you do not have to be at or above the circling minimum to conduct a circling approach. AIP 1.5. 1.7.6(e) and Note says that by day, providing you remain within the circling area, you can descend below the circling minimum altitude providing you maintain the obstacle clearance appropriate to your category and the required circling visibility. AWIS and ATIS may allow you to subtract 100 feet from the circling minimum, but that has nothing to do with the rule.

By night, that option is not available.

Bob

Thanks Bob - once I hear the answer it is always obvious... :unsure: