What is the ruling on combining Dhuhr and Asr prayers in the mosque for someone who is late for congregational prayer, knowing that the Imam has already combined the prayers due to rain?

It is permissible to combine two prayers due to rain that wets clothes, and it is permissible to combine Dhuhr and Asr, and Maghrib and Isha. Combining prayers is a concession for one who prays in congregation in the mosque, provided that the mosque is far from the house entrance such that one is affected by the rain on the way to it. It is not permissible for one who prays alone in his home, or who walks to the prayer area under shelter.