National Weather Service United States Department of Commerce

What to do if you find a weather balloon/radiosonde:


               Vaisala RS92 Radiosonde                                                 LMS-6 Radiosonde                                Vaisala RS41 Radiosonde (No Mail Bag included)


If you have found a National Weather Service (NWS) Radiosonde, it is safe to handle. Photos of radiosondes commonly used by the NWS are shown above.


If the NWS radiosonde comes with a postage paid mailbag (as noted in the instructions printed on the instrument) it can be sent back to the NWS where it may be refurbished and flown again, lowering the cost of the weather balloon program. 

Follow these instructions for mailing the radiosonde to the NWS:

(1) Cut and discard the string to the burst balloon and orange parachute. 

IMPORTANT: On rare occasions the balloon may be found partially inflated with gas. The gas inside the balloon may be flammable hydrogen.  If the balloon is inflated, keep away from it and contact your local fire department for safe disposal.

(2) Remove the plastic mailbag and seal the instrument inside the bag.  NOTE: On the LMS-6 the mailbag is affixed on the plastic tab above the radiosonde.  On the RS92 the mailbag is located inside the plastic tube below the radiosonde.  

(3) Hand the radiosonde package to your mail carrier. Do not leave the package unattended outside a post office mailbox or elsewhere. Postage is prepaid if the instrument is mailed within the United States. If the radiosonde is found in Canada or Mexico, postage is not prepaid, and there is no need to return it.  It should be handled as noted in (4) below.

(4) If the radiosonde is missing a mailbag, is damaged (e.g. exterior casing is crushed), or was found floating in water, it should be disposed of following regulations in your area for handling discarded electronics with depleted lithium batteries.


Thank you for returning the radiosonde you found to the NWS.  More information on NWS radiosondes can be found here:

Fact Sheet