Al-Wasm Season | When do the most beautiful, moderate, and rainy days of the year begin in Saudi Arabia and the Gulf?

Arab Weather - Sinan Khalaf - As soon as October begins each year, memories of the Wasm season and its rains, known for their thunderous nature, begin to linger, reflecting on the soil, which quickly becomes covered with plants, announcing the end of the summer and drought months.

When does the tagging start?

The Wasm season begins on October 16th of each year and continues until December 6th, lasting for 52 days. The Wasm season is called this because it brings greenery and vegetation to the land. If goodness and rain continue during this period, it is followed by a special spring and the appearance of truffles.

Tag entry signs

There are several clear signs of the onset of the Wasm season, including:

• The severity of the hot weather has broken.
• Large temperature differences between night and day.
• The weather tends to be cold at night, especially in the north of the Kingdom.
• The path of the clouds changes, rushing towards the Kingdom from west to east.
• Unstable conditions are forming, and the Red Sea low becomes active.
• Its rains are characterized by frequent thunderstorms and lightning.
• Sandstorms and dust storms are common.
• It is prone to respiratory diseases such as colds and flu.
• The plants turn green and the grass grows.
• This season truffles grow.
• Migratory birds begin to cross the skies of the region.
• Sidr honey is harvested in it

Weather systems prevailing in the region during the Wasm season:

The start of the season and the decline of the seasonal depression:

With the onset of the Wasm season, the seasonal depression begins to recede and retreat, gradually being replaced by the Arabian high pressure system, which is largely responsible for pushing humid air masses from the Arabian Sea towards the Kingdom. This coincides with the presence of the Red Sea low pressure system to the east, which leads to a gradual and continuous drop in temperatures and a break in the intensity of the hot weather.

The tag and the beginning of the Red Sea low activity:

Al Wasm is considered the beginning of the actual activity of the Red Sea depression, as it begins to deepen to affect the Levant and the northwestern parts of the Kingdom. The Red Sea depression also creates atmospheric instability, as it pulls humid masses rushing from the Arabian Sea and pushes them towards the Kingdom, where they interact with the low-pressure systems coming from the north and the Levant region, generating a state of atmospheric instability that leads to the formation of thunderclouds and rainfall.

The impact of Mediterranean depressions:

The increasing activity of the European high pressure system is pushing cold air masses towards the eastern Mediterranean basin, responsible for the formation of extratropical depressions or Mediterranean depressions. The Red Sea low pressure system interacts with the cold Mediterranean depressions, which contribute to the development of unstable conditions and rainfall, which may be thundery and heavy during the Wasm season.

The direct impact of the Siberian high on the region at the end of the season:

At the end of the Wasm season, the Siberian high begins to directly affect the Kingdom, causing a significant drop in temperatures, necessitating the wearing of winter clothing. Temperatures drop, especially at night.

From the memories of the tag:

Strong floods occur frequently during the Wasm season, the most recent of which occurred in November 2013 in the capital, Riyadh, as well as in large areas of the Kingdom, when flash floods formed and heavy rain continued to fall across large parts of the country. The largest floods in the Kingdom also occurred in November 2008, when heavy rain continued to fall for several days. The strength of Wasm has been repeated in many years, most notably 2012, 2004, and 1997. The Wasm period can also be weak, as happened in Wasm 2010.