When flying from Manila to Guanajuato, the time of day you decide to fly out makes little to no difference towards the overall price you’ll pay on tickets.
If you book a flight to Guanajuato from Manila, you will be flying from Ninoy Aquino Intl, which is the city’s only airport. Manila Ninoy Aquino Intl (MNL) is located 10.9 km from the center of Manila.