When is it permissible for the Imam to combine prayers?

Gathering prayers (Jam‘) is a legal concession for the Imam, the congregant, and the individual in specific situations:

1. Hajj: It is prescribed for the pilgrim to combine prayers in ‘Arafat (Dhuhr and ‘Asr, combined at the time of Dhuhr) and in Muzdalifah (Maghrib and ‘Isha, combined at the time of ‘Isha). This is by agreement of the jurists due to its establishment from the Prophet (peace be upon him). 2. Travel: It is permissible to combine Dhuhr and ‘Asr, and Maghrib and ‘Isha (either at the earlier or later time), according to the Shafi‘is, Malikis, and Hanbalis, due to its establishment from the Prophet (peace be upon him). 3. Illness: It is permissible to combine Dhuhr and ‘Asr, and Maghrib and ‘Isha, according to the Malikis, Hanbalis, and some Shafi‘is, by analogy with travel due to the common factor of hardship. 4. Rain that wets clothes and cold: It is permissible to combine Maghrib and ‘Isha according to the majority of Shafi‘is, Malikis, and Hanbalis. They cited the hadith (definition) of Ibn ‘Abbas as proof. 5. Fear: The Hanbalis, some Shafi‘is, and one narration among the Malikis held that it is permissible to combine prayers due to fear. They cited the hadith of Ibn ‘Abbas, "without fear or travel," as proof. 6. Need (provided it is not taken as a habit): Ashhab from the Malikis, Ibn al-Mundhir, Ibn Sirin, and Ibn Shubrumah held that it is permissible to combine prayers due to need. They cited the hadith of Ibn ‘Abbas, "He wanted not to cause hardship to his Ummah," as proof.

As for the Hanafis, they do not permit combining prayers for travel, illness, or any other excuse.