METAR and TAF are the two standard aviation weather products. A METAR is the actual observed weather at an aerodrome — wind, visibility, clouds, temperature and pressure — issued every 30–60 minutes. A TAF, in turn, is the aerodrome forecast for the coming hours.
For drone pilots these reports are the objective basis for a go/no-go decision. A consumer weather app will not tell you the gust strength or the cloud base — METAR and TAF state them precisely, in a single format understood worldwide.