Before launching, pilots will call a weather service to find out about climate and wind conditions in an area. Cautious pilots only fly when the weather is close to ideal -- when skies are clear and wind conditions are normal. Storms are extremely hazardous for hot air balloons, because of the danger of a lightning strike. Even rain is a problem, because it decreases visibility and damages the balloon material (of course, it's not much fun to fly around in wet weather anyway). And while you need a nice wind current to have a good flight, very strong winds could easily wreck the balloon.

Pilots also call the weather service to get a rough idea of which way the balloon will travel, and how they should manoeuvre once they're in the air. Additionally, a pilot might send up a piball (short for pilot balloon). A piball is just a balloon filled with helium that the pilot releases to see the exact direction of the wind at a prospective launch site. If it looks like the wind would take the balloon into prohibited air space, the crew needs to find a new launch spot.