To which weather report are pilots referred to for real-time in-flight weather conditions?

Pilots refer to PIREPs (pilot reports) for real-time in-flight weather conditions because these reports are generated by pilots currently in flight. PIREPs provide first-hand accounts of weather phenomena encountered, such as turbulence, wind direction and speed, cloud cover, visibility, and other significant meteorological conditions observed at altitude. This information is crucial for air traffic control and other pilots, as it reflects the actual conditions in the air.

In contrast, METARs are routine aviation weather reports that provide observations of weather phenomena at specific locations but are typically not real-time during a flight. They are released at set intervals and provide an overview of the weather at the time of the observation. TAFs (Terminal Aerodrome Forecasts) offer weather predictions for airports over a specified time period but do not reflect real-time data. PILOT reports are more general and not as frequently used for immediate in-flight weather assessments as PIREPs. Therefore, pilots rely on PIREPs for timely and relevant updates on weather conditions while flying.