Hadith.674 - Imam Jafar ibn Muhammad Al-Sadiq (as) said:
"The indication of the sun's zenith (midday) is to take a stick that is one cubit and four fingers in length and place four fingers into the ground (embedding the stick partially). When the shadow shortens to its minimum point and then begins to lengthen, the sun has passed its zenith. At this point, the gates of the heavens open, the winds blow, and great needs are fulfilled."