Question:
What is the ruling on reciting Surah Al-Kahf on Friday during the day and night?
Answer:
The recitation of Surah Al-Kahf on Friday is a preferred act and there is merit in it … and there is no difference between a person reciting it from the Book, or by heart … and the day, according to the Islamic law, is from the time of sunrise until sunset … and based upon this, if a person recites it after the Friday prayer, he will receive the reward for it.
Shaykh Muhammad bin Saalih al-`Uthaymeen
Fatawa Islamiyah Vol. 2 Page 477