Because large bodies of water retain heat longer than land, the climate around Lake Baikal is much milder than in the rest of southern Siberia.

Even in the depths of winter the average air temperature is -6°F (-21°C), compared with minimum temperatures of -68°F (-90°C) elsewhere in Siberia.

In August, the average air temperature is 52°F (11°C).

The lake freezes over from January until May or June, but its surface temperature in August is between 50 and 54°F (10–12°C).

Lake Baikal’s water is very clear because it contains very few mineral salts.

From the surface it is possible to see objects 130 feet (40 meters) below.

This clarity is maintained by large numbers of planktonic animals eating floating debris. In spite of its great depth the water in the lake is well mixed, and oxygen is plentiful even in the bottom waters.