In the Middle east there is a system of marriage called Misyar which is a temporary marriage.

Answer

We have written on the haraam practice of misyar 'marriages'. It is simply Shiah mut'ah in a disguised form. It is not permissible. Islam knows only of Nikah. It does not teach or propagate another form of 'nikah' called misyar or mut'ah. If it was genuine Nikah, they would not have labelled it misyar.

The contention that "it is difficult to say that it is completely impermissible", is baseless. The objective (maqsad) of a fatwa is to bring Muslims closer to Allah Ta'ala. The objective is not technical arguments such as dalaa-il discussed in a Madrasah. Statements which embolden people to perpetrate sin and acts which are in conflict with the Maqaasid (objectives)of the Deen should be unambiguously prohibited regardless of technical permissibility. It is indeed despicable for a Mufti to leave a loophole for permissibility for such a dastardly practice so much resembling Shiah mut'ah, when misyar defeats and negates almost all the maqaasid of Nikah. Even if he discerns a slight possibility of permissibility, he should not speak in a manner which opens a door for Fitnah.