@Jocelin ,
I think it’s important to clarify in your post that you do not mean the .wea file used by Radiance since this type of file is much more common in Ladybug Tools workflows (none of Ladybug Tools components make use of the Ecotect .wea file).
To address your question, you will see that, according to fileinfo.com:
WEA files contain weather pattern information and are used for simulation purposes. They are saved in a binary format that can only be opened with Autodesk software.
So, because these files are proprietary, you have no hope of getting the data out of them unless you have a copy of Autodesk Ecotect (or possibly some other utility provided by Autodesk).
It may also be worth clarifying here that we of the Ladybug Tools community are generally of the opinion that we should refrain from using any proprietary file types in our core libraries. While there isn’t too much we can do about .3dm or .gh formats, all of the files used under the hood of Ladybug Tools (.epw, .rad, .idf, .osm, .json, .csv, .sqlite) are open formats. Most of them are readable text and the few that aren’t (like sqlite) are open formats and have parsers in several computer languages. So, if you use Ladybug Tools, you can rest assured that a situation like this will not happen to you with any of the file types we use under the hood.