"Bha i glè ghaothach ann an Glaschu."

Translation: It was very windy in Glasgow.

[Klankers]

In which situations would you use "glè" vs "gu math" for weather?

[silmeth]

They are different intensifiers… I am not a native speaker so cannot answer you exactly, but I think the difference is pretty much as between English very (glè, more explicit) and really (gu math).

[DaibhidhR]

Yes. But im my experience, gu math actually means 'quite' rather than 'really'. I don't think they accept that on Duolingo, but Mark supports me - in a sample I checked he gave lots of examples of quite, one of pretty / rather and none of really.

That means that in my experience is a de-intensifier (although I do not know the correct word for that). D