Jesus is asked for a sign from heaven.....

The Pharisses also with the Saducees came,and tempting desired him that he would shew them a sign from heaven.
He answered and said unto them,When it is evening,ye say,it will be fair weather:for the sky is red.
And in the morning,It will be foul weather today:for the sky is red and lowring.O ye hypocrites,ye can discern the face of the sky;but can ye not discern the times?
A wicked and adulterous generation seeketh after a sign:and there shall no sign be given unto it,.but the sign of the prophet Jonas.And he left them,and departed.
Matthew 15 : 1-4