MySQL Server Time Zone Support •Time Zone Variables •Populating the Time Zone Tables •Staying Current with Time Zone Changes •Time Zone Leap Second Support •The system time zone. When the server starts, it attempts to determine the time zone of the host machine automatically and uses it to set the  system_time_zone  system variable. The value does not change thereafter. •The server current time zone. The global  time_zone  system variable indicates the time zone the server currently is operating in. The initial  time_zone  value is  ’SYSTEM’ , which indicates that the server time zone is the same as the system time zone. •Per-session time zones. Each client that connects has its own session time zone setting, given by the session  time_zone  variable. Initially, the session variable takes its value from the global  time_zone variable, but the client can change its own time zone with this statement: 1000 The session time zone setting does not affect values displayed by functions such as  UTC_TIMESTAMP() or values in  DATE ,  TIME , or  DATETIME  columns. Nor are values in those data types stored in UTC; the time zone applies for them only when converting from  TIMESTAMP  values. If you want locale-specific The session time zone setting affects display and storage of time values that are zone-sensitive. This includes the values displayed by functions such as  NOW()  or  CURTIME() , and values stored in and retrieved from  TIMESTAMP  columns. Values for  TIMESTAMP  columns are converted from the session time zone to UTC for storage, and from UTC to the session time zone for retrieval. If you have the  SYSTEM_VARIABLES_ADMIN  privilege (or the deprecated  SUPER  privilege), you can set the global server time zone value at runtime with this statement: The initial global server time zone value can be specified explicitly at startup with the  --default- time-zone  option on the command line, or you can use the following line in an option file: If set to  SYSTEM , every MySQL function call that requires a time zone calculation makes a system library call to determine the current system time zone. This call may be protected by a global mutex, resulting in contention. To explicitly specify the system time zone for MySQL Server at startup, set the  TZ  environment variable before you start  mysqld . If you start the server using  mysqld_safe , its  --timezone  option provides another way to set the system time zone. The permissible values for  TZ  and  --timezone  are system dependent. Consult your operating system documentation to see what values are acceptable. MySQL Server maintains several time zone settings: For information about time zone settings in replication setups, see Section 17.5.1.14, “Replication and System Functions”  and Section 17.5.1.33, “Replication and Time Zones” . Time Zone Variables Note SET time_zone =  timezone ; SET GLOBAL time_zone =  timezone ; default-time-zone=’ timezone ’