South Texas Weather Modification Association
Current Operational Status:
The operational season has concluded for 2017.  There were 41 seeding missions across
south TX (April: 1, May: 5, June: 7, July: 12, August: 8, September: 7, October: 1).  

More information on past project years can be found on the
Operations page.
The South Texas Weather Modification Association (STWMA) is a non-profit organization
consisting of several water districts committed to enhancing rainfall across the south Texas
operation area.  Rainfall enhancement is conducted using cloud seeding techniques where
aircraft release microscopic particles of silver iodide and calcium chloride into thunderstorms to
increase rainfall efficiency.

The association first formed in 1996 and conducted its first cloud seeding mission the following
year. After 20 years in existence, the STWMA, based in Pleasanton, continues to perform
seeding operations over multiple counties in south-central Texas.

A map of other associated weather modification projects across Texas area can be found

A overview presentation of weather modification in Texas can be found
here. (Provided by the
Texas Weather Modification Association)

Feel free to navigate around the website, whether it's to check our radar image for current
activity, to get the local forecast and conditions for the target area, or read our FAQ page to
learn more about cloud seeding.
Other Active Weather Modification Programs in Texas:
  • Panhandle Groundwater Conservation District:  PGCD
  • Seeding Operations and Atmospheric Research: SOAR
  • West Texas Weather Modification Association: WTWMA
  • Trans-Pecos Weather Modification Association: TPWMA
2019 Project Counties
All Data, Documents, and images on this site are property of the South Texas Weather
Modification Association. Using or duplicating any data, documents, or images is not allowed
unless granted by written permission from the Chairman or webmaster.
Welcome to the
South Texas Weather Modification Association
Information Web Site