El Niño could bring heavier rain to Oman through May 2027

Oman is forecast to experience above-average temperatures during October, November and December 2026. Northern Oman is also expected to receive above-average rainfall in October and November, with another possibility of wetter-than-usual conditions in December. Other areas should generally remain near their climatic averages, except Arabian Sea coastal areas, where October rainfall may be below average.

These conditions could create practical risks. Heavy or very heavy rain may send powerful flows through wadis and affect homes or facilities near channels and low-lying areas. Water accumulation could disrupt roads, while strong winds could damage trees, poles, infrastructure and unsecured objects. Thunderstorms may produce rough seas and hail.

The outlook is seasonal, not a guarantee for every location or day. Temperatures are expected to stay above average, but cold spells remain possible from December through April. The CAA and its National Multi-Hazard Early Warning Centre will continue monitoring conditions and updating assessments.

El Niño is a climate pattern involving unusually warm surface waters in the tropical Pacific Ocean. That warming changes large-scale atmospheric circulation, including the movement of air, moisture and pressure systems. These shifts can influence weather thousands of kilometres away, even though the Pacific is far from Oman.

For Oman, the report links El Niño with rainfall associated with winter weather troughs between October and May. A trough is an elongated area of lower pressure that can help draw or organize moisture and produce unsettled weather. Historical analysis found more rainfall during El Niño years, with the relationship strongest in northern Oman.

El Niño does not determine every weather event or guarantee rain at a particular place. Oman is also influenced by several regional and global climate patterns. The current report expects El Niño to peak in November and December 2026, with effects possibly continuing into 2027.

A 1980–2025 analysis found that Oman received more rainfall on average during past El Niño years. Rainfall was 20 per cent above the climatic average from September to November, 31 per cent higher from December to February, and 54 per cent higher from March to May. The increases grew across the three periods.

These figures describe broad historical relationships, not a promise that Oman will receive exactly those amounts during the current season. They reflect averages across many years and locations. Actual rainfall can vary by governorate, month and individual weather system.

The current outlook points to above-average rainfall mainly in northern Oman during October and November, with a possibility of wetter conditions there in December. Elsewhere, rainfall is generally expected to stay near average, except for below-average October rainfall along Arabian Sea coastal areas. Monitoring will continue as El Niño develops.

The report finds that El Niño’s relationship with increased rainfall is more pronounced in northern Oman. It connects this pattern to rainfall associated with winter weather troughs affecting Oman between October and May. El Niño has historically been linked with increased rainfall and moisture flow, and northern Oman shows the clearest response.

The article does not identify one specific physical reason, such as a particular mountain or coastline effect, for the stronger northern signal. It presents the result as a finding from statistical studies and historical records. This means the northern relationship is an observed pattern rather than a simple rule for every storm.

That distinction matters for the current forecast. Northern Oman is expected to receive above-average rain in October and November, with a possibility of above-average rainfall in December. Other areas are mostly expected to remain near average, while Arabian Sea coastal areas may be drier in October.

If the seasonal indicators develop, Oman could face several connected hazards. Heavy to very heavy rain may cause wadis to flow strongly, threatening homes and facilities in low-lying areas or near wadi channels. Water accumulation could temporarily close or disrupt main and secondary roads.

Strong winds could dislodge unsecured objects and damage trees, electricity poles and other infrastructure. Thunderstorms may bring rough seas, creating danger for fishing boats and other sea users. Hail is also possible in some areas. These hazards can happen together, making local impacts more severe.

The report also warns that electricity, water and telecommunications services could be affected where weather becomes adverse. These are potential outcomes, not confirmed impacts for every location. The centre is assessing risks while monitoring the seasonal outlook, including possible tropical systems in the Arabian Sea during October to December.

The Al Hamayil weather system showed how a deep atmospheric trough can turn heavy rain into widespread disruption in Oman. It affected the country from March 7 to 11, 2016, during a strong El Niño period examined by the centre. Most northern governorates experienced moderate to heavy thunderstorms.

The storm also brought strong winds and hail. Those conditions caused wadis to flow, water levels to rise and flooding to occur in several locations. Al Mudhaibi recorded 120.4 millimetres of rainfall during the period. The example connects intense rainfall with the rapid movement and accumulation of water on the ground.

The event is used as a historical reference, not as a prediction that the same system will return. It illustrates why the current outlook highlights heavy rain, flooding, strong winds and thunderstorms as possible risks. The centre continues monitoring weather developments and seasonal indicators through the coming months.

Oman’s weather reflects several interacting influences rather than one control. El Niño is expected to affect large-scale circulation and moisture flow. Atmospheric troughs can then help produce winter rainfall between October and May. The report links these processes statistically, especially for northern Oman, where the historical rainfall relationship is strongest.

The centre also stresses that warmer temperatures cannot be attributed to El Niño alone. Regional and global climate patterns interact with it and can alter conditions across Oman. Historical analysis found small average temperature increases in autumn and winter during El Niño years, followed by an average decrease of 0.37°C from March to May, especially in northern Oman.

These findings provide context rather than certainty. The 2026 outlook expects above-average temperatures through December and wetter conditions mainly in northern Oman. Cold spells remain possible from December to April, including sub-freezing mountain summits and possible snowfall when suitable conditions occur.