Edouard,
The THSW Index is calculated within the console for display on its own screen but is definitely not available via the data streamed from the console. This has been examined and tested by various sites, and people have been in contact with Davis confining this elsewhere. The WeatherLink software compiles the index within its programming for display on WeatherLink's screen and web tags. WeatherData is where the 45 page database info came from, and they've compiled it into a database that Weather Display uses to calculate its iteration of the THSW Index. In comparisons, the Davis and WeatherD numbers don't always match, but they are close. No one knows how Davis calculates it, so WeatherD does its best to replicate the results.
So WeatherLink only works with Davis stains that provide temp, humidity, solar , and wind readings, and WeatherD works with any station that can provide the same, be it a Vue with a separate solar sensor, an assortment of individual sensors, or a Davis VP2 with solar. WeatherD is much more flexible as towhee it gets its information to calculate and display.
So yes, with WeatherCat's current capability, it would seem a very limited potential audience would want this feature, which would most likely put it at the bottom or not even on Stu's priority list.
Regards,
Steve