Mongolia is a high-altitude country with a cold and dry climate. The nation experiences an extreme continental climate with long, harsh winters and short summers, during which most precipitation falls.

Mongolia enjoys an average of 257 days of sunshine per year, and generally sits within the center of a region of high atmospheric pressure.

Precipitation levels are higher in the North, which receives an average of 20 to 35 centimeters of rain annually, and lower in the South, which receives only 10 to 20 centimeters. In the far southeastern Gobi, certain regions receive virtually no precipitation almost every year.

Average temperatures across most of the country remain below freezing from November through March, and hover near 0°C in April and October. In January and February, temperatures averaging −20°C are commonplace, with winter nights dropping to −40°C. During summer, the hottest days can reach up to 38°C in the southern Gobi, and 33°C in Ulan Bator.

More than half the country is covered by permafrost, making the construction of buildings or roads, as well as mining operations, nearly impossible.

All rivers and freshwater lakes freeze over in winter, and small waterways are often completely ice-bound.

Ulan Bator sits at 1,351 meters altitude in the valley of the Tuul River. Located in a relatively well-watered region of the North, Mongolia's capital receives an average annual precipitation of 31 centimeters, almost entirely falling in July and August. Ulan Bator has an average annual temperature of −2.9°C, with the frost-free period extending from mid-June through late August.

Mongolia's climate is characterized by extreme variability, and during summer, short-term weather forecasting becomes exceptionally difficult. Long-term averages mask significant disparities in precipitation levels, frost dates, and the occurrence of blizzards or spring sandstorms. Such harsh conditions present formidable challenges for communities and make livestock survival precarious. While winters are generally cold and clear, occasional snowstorms—though modest in volume—can blanket grasslands with enough snow and ice to prevent animals from grazing, killing tens of thousands of sheep and cattle. These livestock losses, an inevitable consequence and, in a sense, the natural outcome of such climate conditions, make it difficult to plan for sustainable increases in herd sizes.