What is the ruling on not attending congregational prayer when it rains, and is there a difference based on the severity of the rain?

Congregational prayer is obligatory for able-bodied men, but it is waived in certain situations, including heavy rain that wets clothes or causes mud. This is based on the Almighty's saying: "And He has not placed upon you in religion any difficulty," and "Allah intends for you ease and does not intend for you hardship." The Prophet, peace and blessings be upon him, acted upon this, and Ibn Abbas instructed his muezzin to proclaim: "Pray in your homes" on a rainy day. As for light rain that causes no harm, it does not waive the obligation.