Is it permissible for a woman to perform Tayammum if she fears illness from using cold water for the obligatory ghusl, given the rare availability of hot water?

If ghusl (ritual bath) is obligatory and you are unable to heat cold water and fear harm from using it, then wash what you can of your body and perform tayammum (dry ablution) for the remainder with one strike on earth, with which you wipe your face and hands. This is according to the majority of scholars. Your going to your mother-in-law's house is not an excuse for tayammum. It is advisable to repeat tayammum after the entry of each prayer's time, to avoid the dispute of those who say that tayammum becomes void when the time for prayer exits.