Completely veiled in a layer of eternal cloud-cover, Caligo's plant life is dependent on very little light which filters through the clouds. Many of the trees are very tall, stretching the canopy layer of the forests toward the heavens, so as to soak up more sun for photosynthesis. There are also a lot of fungal-type plants that consume the island.

Parts of the island are completely submerged by water, making the island from an above view appear to be dotted with a few large lakes. Similar portions of the island are low-lying ground where water collects, forming bogs and marshes. Other areas contrast this with lofty mountains and deep canyons with multiple rivers flowing through them.

The average temperatures in the summer months are between 70 and 120 degrees Fahrenheit/21-49 Celsius, and from 50 to 80 degrees Fahrenheit/10-27 Celsius in the winter months, with the coastline being slightly cooler. The average annual precipitation in inches is between 70 and 90.

There is quite a lot of cloud formation over the island, and it is especially pronounced in the upper regions, usually between 5,000-8000 feet. These towering clouds form along the mountains where the incoming trade wind air converges as it moves up a valley and is forced up and over the mountains to heights of several thousand feet. Windward areas tend to be the most cloudy during the summer when the trade winds and associated clouds are more prevalent, while leeward areas, which are less affected by cloudy conditions associated with trade wind cloudiness, tend to be more cloudy during the winter when storm fronts pass through more frequently.

The wind patterns on the islands are very complex. Though the trade winds are fairly constant in speed and duration, their relatively uniform air flow is distorted and disrupted by mountains, hills, and valleys. Local conditions that produce occasional violent winds are not well understood though the general causes of these winds can be surmised. These are very localized winds, observed only in a few areas. They sometimes reach speeds from 60 to 100 mph (160 km/h). Hurricanes pose a severe threat during hurricane season, which lasts from June 1 to November 30, although some storms have been known to form out of season.