<Tr> <Td> blue </Td> <Td> Western European Time / Greenwich Mean Time (UTC) </Td> </Tr> <Tr> <Td> Western European Summer Time / British Summer Time / Irish Standard Time (UTC + 1) </Td> </Tr> <Tr> <Td> red </Td> <Td> Central European Time (UTC + 1) </Td> </Tr> <Tr> <Td> Central European Summer Time (UTC + 2) </Td> </Tr>

Where would you find the greenwich mean time zone how do you know