Saudi Arabia | Will the 2025 Wasm season kick off with heavy, widespread rainfall?

Meteorologists are closely monitoring the latest numerical model outputs via the Arab Weather app . Forecasts clearly indicate that the start of the Wasm season in Saudi Arabia this year, 2025, will be dry. Current data shows no indications of widespread rainfall affecting the Kingdom before the end of October.

When does the wasm season start?

The Wasm season begins on October 16th of each year, and witnesses a radical change in the weather systems in the Arabian Peninsula and the eastern Mediterranean. With the onset of Wasm , the influence of the seasonal Indian low gradually weakens, and an extension of the Red Sea low begins to become active in response to the passage of humid autumnal air masses from the eastern Mediterranean and the Levant towards the Kingdom.

Initial forecasts of a dry start to the Wasm season

However, since the beginning of autumn until now, and despite the arrival of a number of autumnal air masses towards the eastern Mediterranean basin and the Levant region, these air masses have not pushed moisture into the Kingdom's atmosphere. Their impact has been limited to a slight drop in temperatures in the north of the Kingdom, amid expectations that the same weather conditions will continue until the end of October.

Reasons for the weakness of the Wasm season in some years

• The arrival of cold air masses and low-pressure systems towards the eastern Mediterranean is delayed, delaying the onset of the season.
• Surface temperatures are lower than their monthly average, reducing the ability of cumulus clouds to form.
• The strength of the jet stream over the Arabian Peninsula, which weakens atmospheric instability .
• The strength of the low pressure system in the western Mediterranean, which strengthens the jet stream and weakens the wasm.

Influential global factors

The Wasm seasons are also influenced by global factors, such as El Nino and La Nina phenomena and ocean oscillations, which play a role in determining the strength of the season and require careful scientific monitoring to accurately predict the results.