Sometimes, what looks like fake sign language is actually foreign language sign language. Because sign language differs from country to country.

Yes, he’s talking about the weather.

I don’t know enough sign language to say for sure, but I do know that signers are often expressive and mouth words along with signing. It’s actually something I’ve noticed that fakers don’t do, because they don’t have hand motions to match their mouths.

Edit to add, it would help to have audio, because I knew a few of those signs and it might match up with the speech.

Compare this lady

https://www.youtube.com/watch?v=LvNPKwz4Ghw

Or this guy

https://www.youtube.com/watch?v=CujDuBthnOw

Or this guy who seemed to actually know a few words

https://www.youtube.com/watch?v=UIWJwIs3pbI

and here’s some real ASL interpreters

https://www.youtube.com/watch?v=ONlxsY1lbSk

https://www.youtube.com/watch?v=byToG9ZWSM4

Notice the expressions match the tone and specific words.

I’ve only taken an ASL class at the high school level, but facial expression is an important part of signing and adds tone to what you’re saying, so that by itself isn’t really a red flag. He seems to be moving quickly through specific signs rather than just sort of flailing around like fake translators usually do. I can’t understand any of it, but if I had to guess I’d say he’s probably a real translator.