What is so different comparing a TAF with a METAR?

Answer 1

A TAF is an area forecast for the airport that issued it. A METAR is an hourly observation of actual conditions. The METAR will be good for one hour or until replaced by a new one. The TAF is generally valid for 24 hours but a new one is put out every 6 hours. The links below will give you a pretty good explanation of a metar and taf.