Answer
Wa `alaykum As-Salamu waRahmatullahi wa Barakatuh.
In the Name of Allah, Most Gracious, Most Merciful.
All praise and thanks are due to Allah, and peace and blessings be upon His Messenger.
In this fatwa:
The time for reading Surat Al-Kahf extends from sunset on Thursday to sunset on Friday.
In his response to the question, Sheikh Muhammad Saleh Al-Munajjid, a prominent Saudi Islamic lecturer and author, stated:
Surat Al-Kahf may be read during the night or the day of Friday. The night of Friday starts from sunset on Thursday, and the day of Friday ends at sunset. Therefore, the time for reading Surat Al-Kahf extends from sunset on Thursday to sunset on Friday.
Allah Almighty knows best.
Editor’s note: This fatwa is from Ask the Scholar’s archive and was originally published at an earlier date.
Source: www.islamqa.info