Is it permissible to combine the Isha prayer with the Maghrib prayer if there is no rain outside?

Combining two prayers due to rain is a concession, and this is the view of the majority of early and later scholars. Its condition is the presence of rain at the beginning of the first prayer and at the beginning of the second prayer. If the rain stops and no other excuse, such as mud, is present, then the combination becomes invalid, and the second prayer must be re-offered.