How to use weather actions?

Can someone explain to me how to use the weather actions described here:

I tried to do this in my rules:
val humidex = GetHumidex(Temperature, Humidity)

But it just errors out - does anyone have it work who can post me a snippet?

PS using the latest release build.

Did you install the add on?

I have binding-weather1, but do not see a weather addon in the actions tab.

Did you set Paper UI -> Configuration -> System -> AddOn Management -> Include Legacy 1.x Bindings to ON?

Actually, it looks like it might not yet be merged with the baseline, at least as of OH 2.4 M1. You might need to install a snapshot to get access to it through PaperUI, which I do not recommend at this time due to some major problems with the snapshots right now.

You will have to be patient, or run the snapshot I’m afraid. You might be able to manually install the add-on but I suspect it won’t work because of all the changes that are underway to merge ESH back into OH.