It is disliked for him to break his fast on that day, even if he is traveling at the beginning of it; because there are two conflicting reasons: the prohibition for breaking the fast, which is staying, and the allowance which is traveling on the same day, so the prohibition is preferred as a precaution. If he believes that he will not enter the city until sunset, then there is no harm in breaking his fast in it. See: Al-Badai 2: 108, and Al-Hadiyya Al-Alaiyya p.175.