Due to multiple factors, expect to potentially pay more when booking in December. For low rates, October can be a great choice for travel to Ixtapa. Flights to Ixtapa from Santa Ana in October are about $407 on average during October, but can be found for as low as $185.
Regardless of the time of day you decide to fly, the ticket price will remain around the same. Book flights from Santa Ana to Ixtapa as you normally would.