Regardless of the time of day you decide to fly, the ticket price will remain around the same. Book flights from McAllen to Taiwan as you normally would.
In terms of precipitation, rainfall in Taiwan ranges from 2.7 - 11.7 inches per month. June is typically the wettest month, when rainfall can reach 11.7 in. November is typically the driest time to visit Taiwan when rainfall is around 2.7 in.
If weather is an important factor for your trip to Taiwan, use this chart to help with planning. For those seeking warmer temperatures, July is the ideal time of year to visit, when temperatures reach an average of 84.2 F. Travelers looking to avoid the cold should look outside of January, when temperatures are typically at their lowest (around 60.8 F).