We Love Weather Exclusive

What Exactly Are Weather Balloons?

A lot of you have submitted questions and emails regarding weather balloons and how The Weather Channel uses them. So we asked Meteorologist Mike Seidel some questions to clarify the process of using a weather balloon, the type of data it collects, his personal experience with them, and more.

What are weather balloons?
It’s a balloon that carries weather instruments high into the atmosphere to collect and send back weather data.

What are the different types of data they collect?
It measures temperature, moisture, pressure, wind speed and direction.

How do they collect data?
The data is collected by a radiosonde which is very small measuring device (instrument) that is box shaped and attached by a string to the balloon. It sends the information back via radio waves.

Describe the process of sending up a weather balloon from start to finish.
The radiosonde is attached to the balloon and a small parachute and then it’s filled with either hydrogen or helium. It’s then released into the atmosphere. The measurements are then transmitted back to the NWS Forecast Office. It typically takes about 2 hours for the balloon to reach 100,000 feet. And it can be blown more than 180 miles away from where it’s released. Eventually the balloon bursts and the radiosonde falls back to earth.

Who created the first weather balloon?
One of the first people to use weather balloons was French meteorologist Léon Teisserenc de Bort. Beginning in 1896 he launched hundreds of weather balloons from his observatory in Trappes, France. Here is the U.S. the NWS has been taking weather observations with balloons and radiosondes since the 1930s.

Who launches weather balloons?
Weather balloons are typically launched twice a day from around 900 locations in the world. In the U.S. they are launched by a network of upper air stations which include NWS Forecast Offices.

Here is a map of the upper air stations in the U.S. and the Pacific Islands. There are 92 stations in North America and the Pacific islands.  (69 in the lower 48)

Screen Shot 2016-10-25 at 2.45.37 PM
Photo Courtesy: NOAA

And here’s a map of the radiosonde observations worldwide:

Photo Courtesy: NOAA

What material are they made out of?
Weather balloons are generally made out of highly flexible latex.

Have you ever launched one?
I have never actually launched one, but I covered a launching at the NWS Forecast Office in Green Bay, WI in 2016. Here’s a video of me covering the balloon launch which illustrates the process. In this case it was a very windy day and two meteorologists were needed to launch the balloon.


Have you ever found one?
I’ve never found a radiosonde myself but this young girl did back in 2011. Here’s the interview from St. Augustine Beach, FL.

Only about 20% of the approximately 70,000 radiosondes the NWS releases each year are found. A postage paid mailbag is enclosed so you can send it back to be refurbished and used again.

How big are weather balloons?
They are typically about 5 feet in diameter when released. They grow in size as they go up due to the decrease in air pressure.

How high can they travel?
They travel to around 100,000 feet before bursting and returning to earth via parachute.

They burst once the balloon reaches 20-25 feet in diameter. If the balloon bursts before it reaches about 23,000 feet…..or more than 6 minutes of data between the surface and about 23,000 feet are missing, a second balloon may be launched.

How often are they deployed?
They are sent typically sent up twice a day at 00Z and 12Z which is Greenwich Mean Time or Zulu time. This translates to 7 AM/7 PM ET when we’re on standard time and 8 AM/8 PM ET when we’re on daylight time. In important weather situations, some stations will send up intermediate balloons to gather additional data which are fed into the atmospheric models to (hopefully) improve the forecast. This was done during tropical cyclones Hermine and Matthew in 2016.

How long does the process of ascending and descending take?
It typically takes about 2 hours for the ascent and about 30 minutes for the trip back to earth.

It seems like there would be more advanced technology to collect this type of data… why do we use balloons?
There really isn’t anything else that can profile the atmosphere vertically. Sometimes radiosondes are dropped from aircraft which is the case with the Hurricane Hunters that fly into tropical cyclones.

If one of our fans wanted to launch a weather balloon, is there a recommended brand or site you recommend?  Can they create one themselves without having to buy an ‘official’ weather balloon?
You can buy a weather balloon kit on line, but it’s not cheap. This kit costs $700:


If you just want to purchase a weather balloon it’s much cheaper and there are many options. It’s the instrumentation that costs so much.

Join the Discussion


  1. So my question is how do meteorologists get wx data over the ocean or areas that wx balloons aren’t active? Boats? planes? extrapolate between points??

  2. That was very interesting and informative, I have never heard of Weather Balloons before seeing here on We♥ Weather⛅