February 07, 2023

The Truth About Weather Balloons

 There has been a lot of talk about weather balloons this week, and some of the information--from a certain country to our west-- has been problematic.

So let me give you the straight story on weather balloons!

Weather balloons are used by meteorologists to determine weather conditions above the surface.  This is crucial because we cannot understand or forecast weather conditions without detailed knowledge of the three-dimensional structure of the atmosphere.

Two Types of Weather Balloon Systems

Some weather balloons are used to loft weather instruments that radio their observations of temperature, humidity, pressure, and wind back to the surface (see below).  These devices are known as radiosondes. (see below)

Other balloons carry targets that are tracked optically from the ground.  These are known as pilot balloons or pibals and can provide wind information.

Roughly 1000 radiosondes are launched twice a day around the world (see map below)

Do radiosonde and pilot balloons drift long distances around the world, as claimed by certain folks?

The answer is emphatically no.

Weather balloons expand as they rise and eventually burst, subsequently falling toward the ground. That is why all radiosondes have parachutes. 

Want to see a weather balloon rise and burst?  Check out this video on YouTube:

Radiosondes typically ascend to around 100,000 -110,000 ft before bursting, quite a bit higher than the recent Chinese "weather balloon", which was drifting at 60,000 ft.

And weather balloons don't get far before they fall to earth--no more than 100 miles or so, even with the strongest winds aloft.

Long-Range Balloons

There are some companies that are trying to develop long-range balloons that can be used to collect weather data, act as communications hubs, or be applied for other purposes.

For example, a company called Windborne Systems has a long-range balloon that can move up and down from the surface into the stratosphere, taking observations or other tasks.

And Google tried its hand at a long-range balloon that could provide internet to remote locations: their LOON program.  Unfortunately, that project was cancelled in 2021.

Finally, balloons have a long history of use for military surveillance operations, but that is a story for another blog.


  1. Are radiosondes generally retrieved and reused? What if I were to happen upon one?

    1. Cliff has a post about this: https://cliffmass.blogspot.com/2011/10/winning-meteorological-roulette.html

    2. Radiosondes use commercially available (albeit expensive) instruments to collect their data. They are usually recovered pretty quickly since the balloon is tracked, but they are also labelled with the owner's information. Should you find one, you should contact the owner using the information on the instruments. There is nothing hazardous about the instruments. And in the event someone felt the urge to keep them, they should know that they would be pretty useless without the equipment to receive the signals.

    3. I have that same concern. Is it 1k or 2k radiosondes per day? If they aren't retrieved and reused that's a lot of plastics, electronics and other materials fouling our planet.

  2. What are the balloons made of? Are they biodegradable?

    And is there any risk to air traffic with so many balloons going up and payloads coming down each day?

    1. Most weather balloons are polyethylene about as thick as a trash bag, and only weigh a few pounds plus maybe another pound for the radiosonde. There have been a few airplane strikes - nothing serious AFAICT. Note: they are not 200' tall with a ton of payload.


  3. This article is much different from the others. Thank You



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