What atmospheric layer are weather balloons in?

In two hours, a weather balloon can rise above the clouds, higher than the paths of jet planes, passing through the ozone layer in the stratosphere. Reaching altitudes of 35 km (22 miles) or higher, the balloons endure temperatures as cold as -90° C (-130° F). read more

A weather balloon operates in the troposphere simply because this is where the weather happens. As you get up in altitude, the temperature sinks by an average of 0.65 C per 100 meters (about 3 F per 1,000 ft). read more

After an hour, the balloon has ascended to almost 100,000 feet (30,480 meters). This is the stratosphere, the second-to-last atmospheric layer before outer space. Below, the Earth's features are obscured by a thick layer of cloud. Above, the blue sky has faded to dark black. read more