It is “Mustahab” or “preferable” to make Ghusal on the following occasions :
1. Staying at Arafaat.
2. Staying at Muzdalifa.
3. When entering Masjidul Haram.
4. When visiting the Masjid-un-Nabawi.
5. Making Tawaaf.
6. When entering Mina.
7. When stoning the Shaytaan (on the 3 days).
8. Laylatul Baraat (Night of Baraat).
9. Laylatul Qadr (Night of Power).
10. On the night of Arafaat.
11. For the Mawlood-un-Nabi (sallal laahu alaihi wasallam) and when attending all Islamic functions.
12. After making Ghusal for the dead.
13. After the person is cured of madness or illness.
14. After unconsciousness.
15. After intoxication (drunkenness).
16. Before making Tauba.
17. When wearing new clothes.
18. After returning from a journey.
19. For most of the Nawaafil Salaah like Salaatul Istisqa and others.
20. When there is unnatural darkness in the skies.
21. On the afternoon of a very hot day to wash away perspiration.
22. When embracing Islam.