What are the odds that a weather balloon finds its way to a weather company’s CEO’s property? We bet it’s slim! Our weather team was in full-on “geek mode” when our CEO brought in the radiosonde he found near a tree at his place in Wisconsin. The radiosonde has been packed up and ready to mail back to the NWS.

praedictix meteorologists with weather balloon radiosonde

Meteorologists Susie Martin, Tracey Anthony, and Todd Nelson with a retrieved radiosonde.


Weather balloon radiosonde on blue carpet

Weather Balloon Radiosonde

Twice a day, every day of the year, the National Weather Service releases weather balloons to analyze the atmosphere. The instrument attached to the weather balloon, called a radiosonde (seen above), measures pressure, temperature, and relative humidity as it rises. This data is then transmitted back to the National Weather Service. The balloon used to lift the radiosonde is about 5 ft in diameter at launch and is inflated with hydrogen or helium. The balloon will expand due to decreasing air pressure as it rises and will burst when it reaches a diameter between 20 to 25 feet! A parachute attached to the balloon allows the radiosonde to slowly journey back to earth.

Weather Balloon release by National Weather Service Birmingham Alabama showing radiosonde and parachute

Weather Balloon release by the National Weather Service in Birmingham in Alabama

These balloons and instruments are built tough! They’re able to withstand temperatures down to -130°F and air pressure less than 1% of what is found at the surface. If the radiosonde enters the jet stream, it can reach speeds of 250 mph or more! A typical flight lasts for around 2 hours and can rise to 100,000 ft or more into the atmosphere.

Why are weather balloons important?

The data provided by the radiosonde is our primary source of data in the upper atmosphere. This data is valuable because it fuels computer forecast models, arms meteorologists with local information to predict the weather, and is used in weather and climate research. Without weather balloons, accurate forecasts would be nearly impossible. The NWS takes observations at 92 stations: 69 in the contiguous United States, 13 in Alaska, 9 in the Pacific, and 1 in Peurto Rico.

What do I do if I find a weather balloon/radiosonde?

The National Weather Service makes it quite easy to return a radiosonde. Attached to the instrument is a mailing bag and instructions on how to mail the instrument back. Less than 20% of the 75,000 radiosondes launched into the air are found and returned, so if you find one, be sure to take a few minutes to send it back. The instrument will be repaired and reused, saving money and waste.

NWS Weather Balloon mailing package from national weather service

NWS weather balloon mailing package.

Want to learn more about weather balloons? Click here.