The Jeddah Astronomical Society said that Saudi Arabia and other countries in the northern hemisphere will witness the end of the 93-day summer season on Saturday, and the beginning of autumn on Sunday, Sept. 22. This coincides with the beginning of spring season in the southern hemisphere, according to Eng. Majed Abu Zahra, president of the society. He said that the onset of autumn does not mean that temperatures will drop directly, but the decrease in weather will occur gradually over the coming weeks until through the month of November. He noted that autumn is characterized by its many weather fluctuations because it is a transitional period between summer and winter, and hence temperatures fluctuate constantly as it is the actual beginning of the rainy season in many Arab countries. The cases of atmospheric instability increase in regions, including the Arabian Peninsula. There are also more chances of thunderstorms in the Arabian Gulf region in this period. Summer ends in the northern hemisphere during the month of September and night begins early, especially later in the month, coinciding with the return of the planets Jupiter and Saturn to the evening sky. The nights will be shorter for those living in the southern hemisphere during this period and the floor gets warmer as the winter comes to an end.