A.T. Robertson Commentary Matthew 16:3

"And in the morning, [It will be] foul weather to-day: for the heaven is red and lowering. Ye know how to discern the face of the heaven; but ye cannot [discern] the signs of the times." — Matthew 16:3 (ASV)

Lowring (στυγναζων). A sky covered with clouds. Used also of a gloomy countenance as of the rich young ruler in Mr 10:22. Nowhere else in the New Testament. This very sign of a rainy day we use today. The word for "foul weather" (χειμων) is the common one for winter and a storm.

The signs of the times (τα σημεια των καιρων). How little the Pharisees and Sadducees understood the situation. Soon Jerusalem would be destroyed and the Jewish state overturned. It is not always easy to discern (διακρινειν, discriminate) the signs of our own time. Men are numerous with patent keys to it all. But we ought not to be blind when others are gullible.