Jesus wanted the people to see the gap between their skill with the weather and their blindness to what God was doing in front of them. Barnes explains: they saw His miracles, heard His preaching, and had the prophets' predictions, so "why do you not, in like manner, infer that this is the time when the Messiah should appear?" Gill says the evidence was plain enough that "it might have been known he was come." Calling them "hypocrites" shows that their failure was not lack of ability, since they could read the sky (Luke 12:56).

The people's reply is not recorded. Jesus presses the point with another question: "Yea, and why even of yourselves judge ye not what is right?" (Luke 12:57). He then urges them to settle with an adversary "as thou art in the way," before being dragged to the judge and thrown into prison (Luke 12:58-59).

"Discern" translates dokimazō, which the interlinear glosses "to discern"; the ESV renders it "interpret." The word for "time" is kairos, the same word used for the "due season" in Luke 12:42. Barnes summarizes the weather signs simply: "You see a cloud rise, and predict a shower; a south wind, and expect heat."

Matthew records a similar rebuke to the Pharisees and Sadducees who asked for a sign from heaven: "ye can discern the face of the sky; but can ye not discern the signs of the times?" (Matthew 16:1-3).

This question shows that God's work in Jesus was not hidden. The signs were as clear as clouds and wind. Gill calls that moment "the accepted time, and day of salvation." The problem was not missing evidence.

The passage also shows God's patience. Jesus does not simply condemn; He urges. Matthew Henry writes that Christ wants people "to be as wise in the concerns of their souls as they are in outward affairs," and to "hasten to obtain peace with God before it is too late." The story of the adversary on the road (Luke 12:58-59) makes the same point: settle things while there is still time.