New Zealand has two time zones. The main islands use New Zealand Standard Time (NZST), 12 hours in advance of Coordinated Universal Time (UTC) /Military M (MIKE), while the outlying Chatham Islands use Chatham Standard Time (CHAST), 12 hours 45 minutes in advance of UTC /Military M^ (MIKE-THREE). UTC is designated as Military and Aircraft Time Zone Z (ZULU), sometimes referred to as ZERO (as in Zero-Hour offset).