The cheapest month for flights to Chicago O'Hare Intl Airport is September, where tickets cost ₱52,300 on average for one-way flights. On the other hand, the most expensive months are August and July, where the average cost of tickets from the Philippines is ₱76,176 and ₱67,580 respectively. For return trips, the best month to travel is September with an average price of ₱52,300.