John Gill Commentary Luke 12:55

"And when [ye see] a south wind blowing, ye say, There will be a scorching heat; and it cometh to pass." — Luke 12:55 (ASV)

And when you see the south wind blow
From the hot countries of Egypt, Ethiopia, and Arabia, which lay south of Judea:

you say there will be heat ;
or hot sultry weather, scorching heat, which such a wind brings with it:

and it comes to pass ;
generally speaking, as is asserted.