There are no great differences in seasonal temperature on Headquarters Island, its pleasant subtropical climate being augmented by the gentle trade winds.
The wet summer season is between May and October, and the drier winter season runs from November through April. The average temperature is 85, year round.
25% of the island is mountains, most of which contain the underground city. Very few buildings are above ground, the Island having been left as much in it's natural state as possible. The most notable exception to this being the Headquarters building that gives the island it's name.