By far the Scriptures teach that the number one cause for spiritual drought is sin. And the number one cure for drought, according to the Scriptures, is repentance.
In 2 Chronicles 6:26-27, King Solomon is clear in this prayer,
When the heavens are shut up and there is no rain because they have sinned against You, when they pray toward this place and confess Your name, and turn from their sin because You afflict them, then hear in heaven, and forgive the sin of Your servants, Your people Israel, that You may teach them the good way in which they should walk; and send rain on Your land which You have given to Your people as an inheritance.
Notice that the heavens were shut up, there was no rain, because of sin. But when the people confessed God's name and turned and repented, Solomon prayed, "God, hear and open the heavens once again and send rain."
This prayer is particularly significant because Solomon is praying at the dedication of the temple. Scripture declares to us in 2 Corinthians , You are the temple of the living God.
The Old Testament temple was just a type and a shadow pointing to better things—to the era in which God would no longer dwell in buildings made with mortar and stone, but take up residence in human hearts.
That's you and me! As 1 Corinthians tells us, our body is the temple of the Holy Spirit and we are not our own. We have been bought with a price, and God's expectation is that we glorify Him in our bodies. You and I are God's temple.
If there is sin in your life, turn from it and turn to God, so that you can experience the refreshing rain of God's blessing in your life.