The air in Mongolia is often very dry. Relative humidity can be around 10 per cent for days on end. While that is great for drying washing inside and helping you to evaporate your sweat, so cooling you, it can have a harsh effect on your body, causing chapped lips and dry skin. For the nomadic herders and farmers, though, the lack of rain is much more critical.

No rain falls from about early November to late March. There is snow then but it is mostly fairly dry, fluffy stuff rather like icing sugar, and it basically does not melt until spring comes. Summer does bring rain, but it can be "hit or miss". Some areas get quite good falls, often from sudden thunderstorms with local flash floods; other areas get little. And the rain can vary from one year to the next.

Overall, precipitation figures are low. Ulaanbaatar averages 216mm/yr. The figures increase farther north and on the central and western mountains, but decrease southwards into the Gobi Desert.

The extremes relate to many factors. Mongolia stretches over latitudes 42-52 degrees north and is surrounded by land; the sea is a long way away. There are no winds from the sea to moderate the extreme temperatures or to provide more rain. Extremely cold, heavy air moves south from Siberia in winter and sits over Mongolia for weeks on end. (Mongolia holds the world record for the highest pressure ever recorded, 1086 hectapascals.) Much of Mongolia is quite high too. Ulaanbaatar, for example, is 1,350 metres above sea level. The higher the locality, the colder it is.