The Bible warns us that in the last days we would be given signs in the Heavens and Earth to signal the time of the return of Jesus.

Acts 2:19 And I will shew wonders in heaven above, and signs in the earth beneath; blood, and fire, and vapour of smoke: 20The sun shall be turned into darkness, and the moon into blood, before that great and notable day of the Lord come:

The signs and wonders in the sky occur just before the Day of the Lord. Before the wrath of God is about to be poured out, Jesus sends angels to gather the saints into the clouds.

Joel 2:30 And I will shew wonders in the heavens and in the earth, blood, and fire, and pillars of smoke. 31The sun shall be turned into darkness, and the moon into blood, before the great and the terrible day of the LORD come.

A rare event occurred in 2014 and 2015 of four consecutive total lunar eclipses, known as a tetrad This will be followed by a total eclipses in 2017 over the United States.

In 1948 and 1967 the blood red moon tetrad occurred and then again in 1949 and 1950 on Passover and Feast of Tabernacles. There were no tetrads in the 1800s, the 1700s, the 1600s. In the 1500s, there were six, but none of those fell on Passover and Feast of Tabernacles or any feast days. In 1492 when the Jews were removed from Spain there were blood moons.

A complete study of the Blood Moon sign is available as a separate study: http://howlongolord.com/?p=11

Conclusion

Jesus gives many of signs of his second coming. He does tell us that none know the day or hour except the Father. He however does want us to know the season:

Luke 21:25 And there shall be signs in the sun, and in the moon, and in the stars; and upon the earth distress of nations, with perplexity; the sea and the waves roaring; 26Men’s hearts failing them for fear, and for looking after those things which are coming on the earth: for the powers of heaven shall be shaken. 27And then shall they see the Son of man coming in a cloud with power and great glory. 28And when these things begin to come to pass, then look up, and lift up your heads; for your redemption draweth nigh.