But he answering said to them, When evening is come, ye say, Fine weather, for the sky is red;

and he answering said to them, 'Evening having come, ye say, Fair weather, for the heaven is red,

He replied, "In the evening you say, 'It will be fine weather, for the sky is red;'

But in answer he said to them, At nightfall you say, The weather will be good, for the sky is red.

But he responded by saying to them: "When evening arrives, you say, 'It will be calm, for the sky is red,'

But Jesus answered, "In the evening you say 'It will be fine weather, for the sky is as red as fire.'

About the commencement of the evening. By these words Christ reminds them that his power had been sufficiently manifested, so that they must have recognised the time of their visitation, (Luke 19:44,) had they not of their own accord shut their eyes, and refused to admit the clearest light. The comparison which he employs is beautiful and highly appropriate; for, though the aspect of the sky is changeable, so that sometimes a storm unexpectedly arises, and sometimes fair weather springs up when it was not expected, yet the instructions of nature are sufficient to enable men to predict from signs whether the day will be fair or cloudy. Christ therefore asks why they do not recognize the kingdom of God, when it is made known by signs not less manifest; for this proved clearly that they were excessively occupied with earthly and transitory advantages, and cared little about any thing that related to the heavenly and spiritual life, and were blinded not so much by mistake as by voluntary malice.

When it is evening - There are certain signs of fair and foul weather, which ye are in the constant habit of observing, and which do not fail. - The signs of the times: the doctrine which I preach, and the miracles which I work among you, are as sure signs that the day-spring from on high has visited you for your salvation; but if ye refute to hear, and continue in darkness, the red and gloomy cloud of vindictive justice shall pour out such a storm of wrath upon you as shalt sweep you from the face of the earth.

He answered and said unto them,.... Knowing full well their views, and having wrought sufficient miracles to confirm his Messiahship, he thought fit to give them no other answer than this:
when it is evening, ye say, it will be fair weather, for the sky is red; when the sun is setting, it is a common thing for you to say, looking up to the heavens, and observing the face and colour of them, that it is like to be fair weather; no rain, that night, nor perhaps the next day, for the sky is red like fire, through the rays of the sun; which show the clouds to be very thin, and so will soon waste away, and consequently fine weather must follow.

Ye cannot discern the signs of the times. They could read the weather, but were blind to the events (signs of the times) that showed the fulfillment of prophecy, the end of the Jewish dispensation, and the establishment of the Messiah's kingdom.

Luke 12:54.