Is it permissible to combine Dhuhr and Asr prayers due to rain?
Chapter on the Traveler's Prayer
Al-Mughni
Book of Prayer
Primary text
The combination of Dhuhr and Asr prayers due to rain is not permissible. This is the chosen view of Abu Bakr and Ibn Hamid, and the position of Malik. The rationale is that the reported evidences establishing the concession for combination due to rain mention only Maghrib and Isha. The evidence cited by those who permit it for Dhuhr and Asr is not considered authentic as it is absent from the sound collections (Sahih and Sunan), and the statement of Ahmad that he had not heard of it suggests it is invalid. Furthermore, analogy to the combination for Maghrib and Isha is unsound because the hardship there involves darkness and potential harm, which is absent in Dhuhr/Asr. Analogy to travel combination is also unsound because the hardship in travel relates to movement and separation from the traveling group, which is not present here.
Supporting text
There is a secondary opinion, attributed to Abu al-Khattab and the school of al-Shafi'i, that permitting combination between Dhuhr and Asr is acceptable. This is based on a narration that the Prophet, peace be upon him, combined Dhuhr and Asr in Madinah due to rain, and because the underlying cause that permits combination (hardship) would permit it between Dhuhr and Asr, similar to travel.