This extreme heat is, however, exceptional; in most parts of the plateau the summer warmth is tempered by cool breezes from the surrounding mountains, on which there is always a good deal of snow.

At Hamadan, which, though on the plain, is close to the mountains, the thermometer seems scarcely ever to rise above 90 deg., and that degree of heat is attained only for a few hours in the day.

The mornings and evenings are cool and refreshing; and altogether the climate quite justifies the choice of the Persian monarchs, who selected Ecbatana for their place of residence during the hottest portion of the year.

Even at Isfahan, which is on the edge of the desert, the heat is neither extreme nor prolonged.

The hot gusts which blow from the east and from the south raise the temperature at times nearly to a hundred degrees; but these oppressive winds alternate with cooler breezes from the west, often accompanied by rain; and the average highest temperature during the day in the hottest month, which is August, does not exceed 90 deg..
A peculiarity in the climate of the plateau which deserves to be noticed is the extreme dryness of the atmosphere.