Answered by Shaykh Yūsuf Badāt
Question:
Reciting Sūrah Al-Kahf on Fridays – does it need to be done in one sitting or is one allowed to read it in parts throughout the day and when is the last hour that it can be read for Friday? Does one need to recite the entire sūrah or it is acceptable to recite a portion of it, and if so, is there a minimum number of verses to be recited?
Answer:
According to prophetic reports by Dāramī and Ḥākim, it is a sunnah to recite the entire Sūrah Kahf on Friday. The recitation can be completed in parts or in one sitting. The time frame would be, anytime between sunset of Thursday to sunset on Friday.
And Allāh Knows Best