Prayer is an obligation for every Muslim and one of the five pillars of Islam. The five daily prayers are a means of communicating with Allah throughout the day and night. In fact, prayers are tied to certain times that cannot be carried out at regular intervals at any time, but must follow the instructions of the Al-Qur'an and As-Sunnah. in this research, The problem to be studied is the influence of altitude and the brightness of the sky determines prayer times. To answer In this problem the author uses a qualitative descriptive-normative approach. In In this modern era, it will not be difficult for us to know prayer times because there are many Islamic mass organizations, even the government makes prayer time schedules as a reference performance of prayer. However, we need to know prayer times based on natural phenomena that occur, so that our knowledge is more comprehensive. Da- In practice, several scholars hold the same opinion regarding the interpretation of hadith regarding determining prayer times as exemplified by the Prophet. But there is There are also some scholars who have different opinions regarding the interpretation for determination some prayer time. For example, the opinion of Imam Syafi'i and Imam Hanafi egarding the beginning of the time for the 'Asr prayer and the Isha prayer, there are different opinions in the interpretation of the hadith of the Prophet Muhammad