The third group of atmospheric phenomena, humidity and precipitation, possesses the same great uniformity in Ukrainian territory as the other two elements of the climate. [94]The humidity of the air in the Ukraine is in general slight. It is greatest in the forest-covered partly swampy West and Northwest. Toward the southeast the humidity in the Ukraine constantly decreases. Fogs appear seldom and are only light, so that the antithesis to Western and Central Europe, as well as Russia, is striking. The light night and morning fogs which appear, especially in the latter part of summer and in the fall, only contribute to the beautification of the landscape, by flooding the depressions of land like a sea. Cloud-formation is much slighter in the Ukraine than in Western or Central Europe, or in Russia proper, the dreary Muscovite country. The greatest number of clouded days occurs in the western and northwestern part of the Ukraine; toward the southeast and east the number of such days dwindles continuously. The least amount of cloudy weather occurs in the month of August. In September and October the increase is very slight. November and December are much cloudier and January is most cloudy all over the Ukraine. After that the cloudy weather lessens considerably at first, then slowly, until August. The atmospheric precipitations in the Ukraine are in general insignificant, except in the Carpathian and Caucasus regions. The Ukraine has less rainfall than Central or Western Europe. The Atlantic Ocean, the most important source of the precipitations in Europe, lies far distant, and the cyclonal systems on their way east drop their collected moisture upon Western and Central Europe. For the Ukraine, and particularly for the eastern part of it, there is, therefore, very little left. In this connection the Black Sea has only a local significance, and the evaporation of water from the rivers, lakes and swamps, from the plants and the ground, is hardly worth considering, except as it happens in the summer.