Map from Google - Mongolia

In Mongolia the climate is strongly continental, with long frigid winters, and short warm summers: the temperature range between winter and summer is definitely wide.
Precipitation is scarce, and is concentrated in summer, when the country is partly affected by the Asian monsoon; in winter, when a thermal high pressure system dominates, the skies are often clear. Precipitation is more abundant in the north, where it exceeds 300 millimetres per year, while in the south, which is actually desert, it drops below 200 mm per year. During winter, snowfalls are frequent but usually light, so that they create a thin white veil which can be carried away by the wind; sometimes a light snow can fall even when the sky is clear: moisture condenses directly, because of the very cold temperatures.
Much of Mongolia is occupied by a plateau at an altitude between 1,000 and 1,500 metres, which temper the summer temperatures. In the plateau strong winds may blow, especially in spring. Due to the aridity of the climate, these winds can bring dust storms, which are more frequent in the south (where they occur more than 30 days per year), quite frequent in the central part (15 to 30 days per year) and very rare in the north (even less than 10 days). In winter the wind associated with the outbreaks of cold air masses, can amplify the feeling of cold and lead to rapid frostbite, if one is not properly dressed: for example, with a temperature of -20 °C, which is normal in Mongolia during the cold months, a wind of 72 km/h generates a wind chill (equivalent temperature) of -35 °C, and therefore the risk of freezing. When the temperature plunges below -30 °C, in case of prolonged exposure there's some risk of freezing even in the absence of wind.
The climate in Mongolia is unstable, so from year to year there may be significant variations in temperature and rainfall.

Steppe in Mongolia

The amount of sunshine in Mongolia is good throughout the year, because clear skies are frequent, reaching a maximum in spring; in summer the number of cloudy days increase a bit, because of the aforementioned summer Asian monsoon.
The average temperature in January goes from -32 °C in the coldest areas of the north, to -15 °C in the south. The temperature does not necessarily decrease with altitude, on the contrary, for the phenomenon called temperature inversion, it may even increase with altitude: the colder areas of the country are the valleys between the mountains of the north. On the contrary, in summer the temperature rises proceeding from north to south and going down in altitude: at 1,500 metres above sea level, the July average is around 13 °C in the far north, 15 °C in the centre-north and 20 °C in the south, while at 1,000 metres, it goes from 16 °C in the north to 23 °C in the south. So, only at lower altitudes and in the south, the summer can be considered hot. The areas located at lowest altitudes, around a thousand metres or less are not very large; so in most of Mongolia the summer has generally cool nights (sometimes even cold) and pleasant days, even though in the whole country, heat waves with peaks of 35/37 °C are possible, at least below 1,500 metres.
The northern part of Mongolia lies in the permafrost area (the southern limit is more or less the latitude of the capital), in which the ground below a certain depth remains frozen throughout the year, and makes it difficult to build houses and infrastructures, and to dig for the extraction of raw materials.

In addition to the plateau, in Mongolia there are mountain ranges: in the west the Altay Mountains, which reach the highest point in Hüiten Peak, 4,374 metres high, in the west-central the Khangai Mountains, reaching 4,000 metres, and north of the capital the Khentii Mountains, reaching 2,800 metres. The mountainous areas are those that receive more abundant rainfall, and they are practically the only ones where you can find woods. Above 3,500 metres, there are glaciers and snowfields, while at lower altitudes, above 2,000 metres, sometimes it can snow even in summer.
The Gobi Desert is located in the south, and although it is drier than the north, it receives some rain showers in summer, able to feed some grass and the camels, at least in the east, where 150 to 200 mm of rain per year fall. The most arid area is the south-west, where less than 100 mm per year fall, and in some cases less than 50 mm.
Here is the average precipitation of Sainshand, located in the south-east, at 950 metres above sea level.
Average precipitation - Sainshand
Prec. (mm)1123815303010521111

In summer, the temperatures in this area are high, as we can see from the averages of Sainshand.
Average temperatures - Sainshand
Min (°C)-23-20-11-171417158-1-12-20
Max (°C)-12-7314232829282112-1-10

The main lakes of Mongolia are: Khar-Us, 1,150 metres above sea level in the west, in a desert area, Uvs in the northwest at 760 metres, also in a desert area, where the average temperature in July is around 19 °C, and finally Khövsgöl, which is located at 1,650 metres in the north, in an greener area, and given the high altitude and its size (which makes it able to create a local microclimate), on its banks it's very cool or cold even in summer.

The capital Ulaanbaatar (Ulan Bator) is located in the north, at 1,300 metres above sea level, and is relatively rainy, not only for the northern position, but also for its proximity to the mountains (the aforementioned Khentii in the north, and a single mountain, Bogd Khan in the south), so that it receives about 300 mm of rain or snow per year. During winter it's the coldest capital in the world, having a January average of -20 °C. The minimum at night drops easily below -35 °C; on January 2012 it dropped for a consecutive week below -40 °C, with a peak of -44 °C, while in January 2001 it reached -45 °C. The daily average is around 0 °C in April and October. In May and September, lows are around freezing and highs around 15 °C, but given the climate variability, sometimes there can be intense frosts even in these months. During winter, snowfalls occur frequently but they are light. The sky is often clear, although in the coldest hours a mist may form. Summer is pleasant: highs in July and August are about 22 °C, with cool nights, around 9/11 °C. Occasionally it can get cold even in summer, while during the day it can get hot: the temperature rarely exceeds 32/33 °C, but sometimes it can reach 37/38 °C.
Here are the average temperatures.
Average temperatures - Ulaanbaatar
Min (°C)-25-22-14-5281082-5-14-22
Max (°C)-14-9-1917212219148-3-12

Summer is also the rainiest season: from June to August, more than 50 mm of rain per month fall, usually in the form of showers in the afternoon. Here is the average precipitation.
Average precipitation - Ulaanbaatar
Prec. (mm)22381550657530853270


At higher altitudes, the summer temperatures become cooler, as we can see from the averages of Altay, at 2,200 metres above sea level.
Average temperatures - Altay
Min (°C)-25-23-15-706861-7-16-21
Max (°C)-13-9-1512181818133-3-8

When to go

The best time to visit Mongolia is the summer, from June to August, when the temperature, at least in the plateau and the mountains at low altitude, remains above freezing even at night. Summer is certainly the rainiest period of the year, and during the day it can be hot especially in south-central and at lower altitudes, but at least you avoid the bitter cold. However, in summer it can get cold at night, so you have to be ready to cover and uncover, depending on hour and weather conditions.

What to pack

In the winter: clothing for the cold, synthetic thermal long underwear, fleece, parka, wind jacket, hat, gloves, warm boots.
In the summer: spring/autumn clothes, T-shirts for hot days, long jacket for the wind, sweater or sweatshirt for the evening and high altitudes, raincoat or umbrella, scarf for the wind-borne dust, hiking shoes, sunscreen, sunglasses. For the high mountains, down jacket, hat, gloves, scarf. For overnight stays outdoors, sleeping bag, warm jacket.