Matthew 16:3-4

3And in the morning, ‘It will be stormy today, for the sky is red and has a threatening look.’ You know how to interpret the appearance of the sky, but cannot interpret the signs of the times?

4An evil and [morally] unfaithful generation craves a [miraculous] sign; but no sign will be given to it, except the sign of [the prophet] Jonah.” Then He left them and went away.