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**Article Three**
It states that a quarter of the world is divided into seven true climates.
Know, esteemed one, that astronomers have said: They have divided a quarter of the inhabited earth into different regions based on the differences between night and day, and they have given each of these regions a name – climate. They explained the northern part of the globe, comparing it to the condition of the southern part, and partitioned the entire Earth into sixty-two climates. Accordingly, they determined the distinction of true climates sometimes by the length of the longest day and other times by the number of months. For those located in the equatorial region experience twelve hours of daylight and night constantly. Thereafter, as one gradually moves towards the south pole and north pole from the equator, the differences between night and day increase. Consequently, they assumed that there were circles parallel to the equator and considered the space between each pair of these circles as a climate, provided that the longest day in that region was half an hour longer than that of its neighboring region on the equatorial side.
With the aforementioned division, the natures, locations, and differences in night and day of the regions have been collectively determined and recorded in a table.
For (in a classification based on these divisions) cities located within the same latitude share common values in terms of nature and location, thus becoming equal in terms of climatic conditions. It is assumed that there are three circles in the first climate: one at its beginning, another at its middle, and a third at its end. As for the remaining climates, it is assumed that each has two circles, one at its middle and the other at its end. For here, the end of each climate is defined as the starting point of the next.
Earlier philosophers limited the number of climates to only seven and did not conceive of climates beyond the fiftieth latitude. However, later scholars ascertained that the lands behind these seven climates were populated and inhabited, progressing as far as sixty-six and a half degrees of latitude, reaching the turning point of the constellations' pole. They continued the division by adding half an hour to the longest day, thus finding twenty-four climates. Then, adding one month to the longest day, they continued the division until they reached the poles at the ninetieth degree, determining all of them as thirty-two climates. However, since most of the equatorial regions are covered by seas, it is generally accepted among scholars that the beginning of the first climate starts from a latitude of twelve and a half degrees. The longest day in that region has been found to be approximately twelve and a half hours. Therefore, the place where the longest day increases by a quarter of an hour is the middle of this first climate. The place where the longest day is thirteen hours marks the end of the first climate and the beginning of the second. In this case, as we progress adding half-hours to the length of the longest day in each climate, when we reach the twenty-fourth climate, it is observed that the longest day at that point is twenty-four hours. That is where the turning place of the northern constellations' pole is located. However, these climates are small in size.
For the length and breadth of the first climate’s distance is always less than the breadth and length of the second climate. All climates proceed according to this arrangement and each is narrower and smaller than the last. Nevertheless, the latitude of the climates begins at the equator and ends at the poles (at the ninetieth degree).
The longest climate is considered to begin from the Khalidat Islands located in the Western Ocean and end in the Eastern Ocean.