What is the primary function of onboard weather radar in an aircraft?

The primary function of onboard weather radar in an aircraft is to detect and avoid hazardous weather conditions. This technology allows pilots to visualize weather patterns, such as storms, precipitation, and turbulence, by providing real-time information about the environment surrounding the aircraft. By interpreting the radar data, pilots can make informed decisions regarding flight paths, helping to ensure safety and comfort for both the aircraft and its passengers. Effective use of weather radar is crucial during takeoff and landing phases, as well as during flight, particularly in adverse weather situations.

The other options represent functions that are not related to weather radar. Monitoring fuel levels is typically done through fuel gauges and sensors, while aircraft speed is tracked using pitot-static systems. The assistance in navigation to air traffic control centers involves navigation systems and communication, rather than weather radar.