You’ll likely spend much of your trip indoors, but if you want to see more of the area, taking a look at local weather data can help you. The hottest months are usually January and February with an average temp of 81°F, while the coldest months are July and June with an average of 64°F. The rainiest months in Formosa are November, October, December, and April, with each month seeing an average of 7 inches of rainfall.