Yom’s atmospheric pressure at sea level measures about 70 percent of Earth’s, although it has a slightly higher percentage of oxygen in its air. Yom inclines 36° toward its ecliptic plane, considerably more than the 23 1/2° of the Earth. This inclination causes more extreme seasonal temperature variations and causes its tropical and arctic regions to be proportionately much larger than Earth’s. Yom’s average temperature approximates Earth’s, though its polar regions turn colder in winter and its equatorial regions remain unbearably hot. As on Earth, local conditions greatly influence local climates. For example, the high altitude of some equatorial regions makes them comfortably cool.
Yom’s most unusual climatological features are the frost-free areas of the Phecda and Triomn continents. The high volcanic activity of these areas has created subterranean geothermal “oceans” which warm the ground. Although not really hot enough to affect air temperatures, the warm ground does prevent the buildup of snow during the winter months, allowing both animals and plants which could not otherwise live in arctic regions to survive.
Yom’s day, from which it derives its name, is the second longest among the Human colonies, measuring 27 standard hours. The longer day causes daily temperature extremes slightly higher than Earth’s, but the difference creates no significant discomfort for Humans.