Complex sentence: Horse latitudes or subtropical highs are subtropical latitudes between 30 and 38 degrees both north and south where Earth's atmosphere is dominated by the subtropical high, an area of high pressure, which suppresses precipitation and cloud formation, and has variable winds mixed with calm.
Split into simpler sentences: Horse latitudes or subtropical highs are subtropical latitudes between 30 and 38 degrees both north and south. This region, under a ridge of high pressure called the subtropical high, is an area which receives little precipitation and has variable winds mixed with calm.