At the beginning of the scene, why does benvolio think that there will be a fight?

It's hot outside, tempers are too, and the Capulets are out as well as the Montagues.

The feud between the Capulet and Montague is deep. to show this Shakespeare puts this fight in the play. Benvolio knows theirs going to be a fight because the tension is huge and the fudge is just to strong. i may be wrong but i had the same question and said this and got is right but who knows.