Is it permissible to pray in the mosque with tayammum when water is unavailable or out of fear of illness due to the cold weather?

Tayammum is not permissible except when water is unavailable or one is unable to use it, as Allah says: "And you find no water, then perform Tayammum with clean earth." Therefore, performing Tayammum in a settled area when water is available and one is able to use it is not permissible according to the majority of scholars, and purification with water is obligatory. If you are unable to use water due to harm or severe cold, then you may perform Tayammum and pray with it in the mosque.