Vulcan (planet)/Temperature and climate
|Memory 118 Guide •|
First and foremost, Vulcan is a hot planet. Daytime temperatures routinely range from 43.3ºC (110ºF) to 51.6ºC (125ºF), and in the peak of summer can reach or exceed 65.5ºC (150ºF). The rays of Vulcan's orange sun, 40 Eridani A, usually shine down through the red sky unbroken by clouds from dawn to dusk, as rainfall throughout the planet typically averages less than 635mm (25in) per year and is heavily concentrated in the six-week period immediately following summer's end. In addition, winds tend to be mild except along the coasts, providing little relief. (The exceptions, the continent-spanning sandstorms, provide no relief at all.) Only nightfall brings a break to the incessant heat, dropping the thermometer to 7ºC (45ºF) or below. In Vulcan's winter months, the mid-latitude deserts often experience freezing temperatures at night.
In addition to the searing heat, Vulcan has a gravitational pull 1.4 times that of Earth, and a thinner atmosphere (due to the long-term effect that 40 Eridani A's solar flare activity has had in eroding the planet's upper ionosphere). As a result, the planet's surface receives more ultraviolet radiation from the sun than Earth. Over time, of course, Vulcan physiology has adapted to this environment, providing its people with a secondary eyelid to reduce glare and keep out foreign particles, and reducing the body's daily, needs for liquids and other nourishment.
As a result of adapting to survive such rigors, Vulcans in Earth-normal environments posses a physical strength and sensory acuity (particularly hearing) well beyond the human norm. Conversely, humans visiting Vulcan for the first time are apt to wilt quickly upon exposure to these hostile conditions. Protective eyewear (either sunglasses or refractive goggles) is very helpful. Moreover, any human planning to engage in physically demanding activities (such as mountain climbing, hiking, physical training or a ceremonial combat like the koon-ut-kal-if-fee) needs to receive regular injections of a tri-ox compound (available in starship infirmaries, or in the visitors' quarter of ShirKahr) to avoid becoming quickly exhausted and dehydrated. Humans who remain on Vulcan for an extended period of time will find that their bodies will adapt over time, though not completely to Vulcan tolerance levels. Frequent medical check-ups are recommended, as the chance of developing respiratory ailments can be heightened, especially among those of advanced age.
The planet Vulcan has no axial tilt, so that there is no natural progression of the seasons from north to south and back again as on Earth. Instead, seasonal changes occur planet wide as the result of Vulcan's elliptical orbit around its sun. At its perigee, Vulcan passes less than 0.56 AU (83.6 million kilometers, or 52 million miles, or closer to its sun than Venus is to Sol) from the roiling surface of 40 Eridani A; during this time, solar flares can still make their presence felt on the planet, causing tectonic activity in the still shifting plates which lie beneath unstable geological zones like the island continent of Xir'tan or the Fire Plains of Raal. During these months, the seismologists at the Vulcan Science Academy remain constantly vigilant, diverting travelers and mining expeditions away from possible earthquake zones, monitoring the status of over 200 active volcanoes, and coordinating evacuation and rescue activities in the event of a disaster.
The majority of this information has been taken from The Way of Kolinahr Sourcebook, with modifications from other sources.