What does a weather balloon do exactly? Learn what a weather balloon looks like and how they collect real-time data in the sky on winds, pressure, temperatures and moisture. ACCURATE FORECASTS WOULD BE ALMOST IMPOSSIBLE WITHOUT WEATHER BALLOONSDuring its missions, researchers work to keep the massive balloons over international waters, but where land crossings are needed, the U. A future balloon is expected to carry the Extreme Universe Space Observatory 2 project, which will detect and observe ultra-high energy cosmic-ray particles