I was wondering how long is the METAR report valid for after issuance? I know some airports issue them every 30 minutes and some every hour. So I wanted to know if a METAR is issued at 8:30AM then will it be valid till next Metar report i.e. 9:00AM or is it just valid for 10-15 minutes after that ?
A METAR is a report of conditions at a specific time, so it's only valid when it's issued. It's not a forecast, the weather could be different 5 minutes later. TAFs are forecasts that have a time range, they are valid during that time range. That doesn't mean they are guaranteed to be correct, it's just a prediction.