What causes the gobi desert to be so hot and cold

Though the region doesn't receive much water during the rainy season, the Gobi receives more moisture during the winter. The Siberian Steppes, north of the Gobi, are responsible for much of the snow that appears on the desert. High winds sweep the snow from the Steppes, distributing it over the dunes of the Gobi during the winter months. Because most of the desert is actually rock rather than sand, however, even this extra moisture has little effect on the region's ecosystem. 

These high winds are also the major cause of the temperature extremes common to the Gobi. Both cold and hot air are swept across the desert unhindered. The environment of the Gobi can be harsh and unforgiving, but the area remains an important piece of history and culture to the world.Most deserts suffer from rapid changes in temperature throughout the year, but the Gobi has a climate of extremes. The temperature has been known to shift 60 degrees Fahrenheit in as little as 24 hours. It can get down to minus-40 degrees in the winter, and as hot as 122 degrees in the summer. Though the desert only receives an average of 7.6 inches of rainfall per year (compare that to the Amazon Rainforest which recieves 9 feet), but that's not the only precipitation. Thanks to region's height above sea level (up to 5,000 feet in some areas) and northerly position on the globe, it's not unheard-of to see frost or even snow atop the dunes occasionally.

So  if  the sum of the enthalpies of the reactants is greater than the products, the  reaction  will be  exothermic.  if  the products side has a larger enthalpy, the  reaction  is  endothermic. you may wonder why  endothermic reactions, which soak up energy or enthalpy from the environment, even happen