Is it permissible to recite Surat Al-Mulk in the morning, at noon, or in the afternoon before sleeping, for someone who is accustomed to sleeping at those times and does not sleep at night, knowing that the recitation of Surat Al-Mulk is (usually done) at night?

There is an emphasis on reciting Surat Al-Mulk every night, and that Allah will protect whoever recites it every night from the torment of the grave. Other hadiths also mention the desirability of reciting it before sleeping. The general principle for bedtime supplications is that they are for nighttime sleep, but there is no harm in reciting them for daytime sleep, especially if a person does not sleep at night. Therefore, there is no impediment to reciting Surat Al-Mulk when sleeping during the day, and it is hoped that one will attain the promised reward for reciting it before sleep.