2025–26 South-West Indian Ocean cyclone season
The 2025–26 South-West Indian Ocean cyclone season is the current annual cycle of tropical cyclone and subtropical cyclone formation in the South-West Indian Ocean. It officially began on 15 November 2025, and will end on 30 April 2026, with the exception for Mauritius and the Seychelles, for which it will end on 15 May 2026. These dates conventionally delimit the period of each year when most tropical and subtropical cyclones form in the basin, which is west of 90°E and south of the Equator. However, tropical cyclones can form year-round with any cyclone forming between 1 July 2025 and 30 June 2026, such as 01, Awo, Blossom and Chenge, will be part of the season. Tropical and subtropical cyclones in this basin are monitored by the Regional Specialised Meteorological Centre in Réunion and unofficially by the Joint Typhoon Warning Center.
Seasonal summary
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Pre-season/early season activity
The season began with the crossover of a tropical low from the Australian basin on 16 July. The low was designated [|Tropical Depression 01] by Météo-France, while the JTWC designated the depression as Tropical Storm 01S a little later. The system did not strengthen and dissipated 2 days later without affecting land. On 7 August, a tropical disturbance formed well north of the Mascarenes, later that day it was upgraded to a tropical depression then subsequently named Awo that evening as it strengthened into a Moderate Tropical Storm. Awo was the first named storm to form in August within the South-West Indian Ocean basin since Severe Tropical Storm Aline in 1969, though Severe Tropical Storm Tony did enter the basin during August in 1979. Awo only briefly survived, encountering high shear and dissipating the next day. On 7 September, Météo–France started monitoring a disturbance south of Diego Garcia. Briefly on 9 September, it intensified into a tropical depression. The system was then classified as a Moderate Tropical Storm and named Blossom, becoming the second named storm of the season. Blossom maintained its intensity in a marginal environment, before degenerating into a remnant low–pressure area on 11 September. On 17 October, a low–pressure area formed near Diego Garcia and was marked by Météo-France as the fourth Zone of Disturbed Weather of the season, the fourth off-season system of the season. After strengthening into a Moderate Tropical Storm, it was named Chenge. Heading westward, the cyclone further strengthened into a Severe Tropical Storm on 22 October before weakening. On 25 October, Chenge degenerated into a remnant low off the coast of Tanzania.Following these early and off-season systems, the basin experienced a prolonged period of inactivity leading into the official start of the season. Activity resumed on 27 December when Tropical Cyclone Grant entered the South-West Indian Ocean from the Australian region, retaining its name as it crossed basin boundaries. Grant dissipated in early January, and five days later, on 10 January, Cyclone Dudzai developed, becoming the second intense tropical cyclone of the season. Dudzai’s formation marked a transition to more typical mid-season conditions, characterized by warmer sea-surface temperatures and reduced wind shear, which supported stronger and more sustained cyclonic development within the basin.
Systems
Tropical Depression 01
On 16 July, a tropical low moved from the Australian Region into the South-West Indian Ocean, where it was classified as Zone of Disturbed Weather 01 by Météo-France. On the same day, the JTWC upgraded the system to a tropical storm, assigning it the designation 01S. The system moved west-southwestwards into an increasingly unfavourable environment, dissipating on 18 July.Moderate Tropical Storm Awo
On 6 August, a tropical disturbance formed in the central Indian Ocean. A day later, the JTWC designated the system as Tropical Storm 02S, while MFR designated the system as Tropical Depression 02. Six hours later, Mauritius Meteorological Services upgraded it to moderate tropical storm status and named it Awo.Awo is the first named storm to form in August within the South-West Indian Ocean basin since Severe Tropical Storm Aline in 1969, though Severe Tropical Storm Tony did enter the basin during August in 1979.
Moderate Tropical Storm Blossom
Meteo-France Réunion began monitoring a disturbance on 7 September. At 10:00 a.m. on 9 September, MFR upgraded it to Tropical Depression status, marking it as Tropical Depression 03. By the next advisory it weakened back to a Tropical Disturbance. On 10 September it once again intensified into a Tropical Depression. On 11 September, it strengthened once again, this time strengthening into a Moderate Tropical Storm, thus receiving the name Blossom. It weakened shortly after and dissipated the next day.Severe Tropical Storm Chenge
On 17 October, a low–pressure area formed near Diego Garcia and was marked by Météo-France as the fourth Zone of Disturbed Weather of the season. It was then classified as Moderate Tropical Storm Chenge. Early on 22 October, Chenge intensified into a Severe Tropical Storm. Chenge then went on to move in a mostly western trajectory, passing north of Madagascar before entering increasingly unfavorable conditions and weakening into a Tropical Depression.Intense Tropical Cyclone Grant
On 27 December, Grant entered the basin from the Australian Region at 10:00 RET as a severe tropical storm. Twenty-four hours later, the system became a tropical cyclone. After rapid intensification, Grant was upgraded to an intense tropical cyclone at 0:00 UTC on December 29, equivalent to a Category 3 hurricane on the Saffir-Simpson scale, about 1300 km southeast of Diego Garcia, the first major cyclone of the season in the South-West Indian Ocean Basin. At 15:00 UTC, the Joint Typhoon Warning Center upgraded it to category 4. Grant remained at slightly below its peak intensity for more than 42 hours before weakening back to a tropical cyclone, according to RSMC La Réunion, on December 31 at 12:00 UTC, as it entered an area of dry air and upper-level wind shear. It was then 900 km east-northeast of Rodrigues. On January 1, 2026, at 6:00 UTC, Grant was downgraded to a severe tropical storm and then to a moderate tropical storm 6 hours later, more than 600 km northeast of Rodrigues. The next day at 12:00 UTC, the system was downgraded again, this time to a tropical depression. On Sunday, January 4th, the center of the system passed about North of St. Brandon, bringing bands of heavy showers and thunderstorms with swells of 3 to 4 meters. On January 5, the Regional Specialized Meteorological Centre La Réunion issued its final bulletin for Grant, which had weakened into a tropical disturbance passing between 50 and 100 km southeast of Tromelin Island. The remnants of the system were heading towards the southern coast of the Toamasina Province in Madagascar, which it was expected to reach within two days.Intense Tropical Cyclone Dudzai
At 12:00 UTC on 10 January, the RSMC La Réunion estimated that a tropical disturbance it had been monitoring for a few days was sufficiently organized to be declared a tropical depression at 800 km southeast of the Chagos Archipelago. Later that day, it was given the name Dudzai as it intensified into a moderate tropical storm. Dudzai would then strengthen into a severe tropical storm the following day. By 12 January, it had rapidly intensified into an intense tropical cyclone. Dudzai then encountered less favorable conditions and its very slow movement produced an upwelling of cooler water from the depths, all leading to a gradual weakening. On 13 January, its trajectory also turned westward. On 14 January, the system temporarily weakened back to a strong tropical storm, while accelerating towards the Mascarene Islands, before returning to a tropical cyclone with an improvement in environmental conditions. On 15 January, Dudzai restrengthened into an intense tropical cyclone and increased its gale-force wind radius. On 16 January, Dudzai reached its second peak intensity with maximum sustained winds of 195 km/h and a minimum central pressure of 945 millibars. Soon after reaching its peak intensity the cyclone began to weaken due to an eyewall replacement cycle. On 17 January, Dudzai weakened back into a severe tropical storm and a cyclone warning was issued for Rodrigues island by the Mauritius Meteorological Services. On 18 January, the center of the system moved approximately 180 km southeast of the island where Air Mauritius had cancelled all flights to and from Rodrigues. The storm then passed approximately 300 km southeast of Réunion and Mauritius, both of which were placed on weather warning due to the effects of the cyclonic swell on sea conditions and potential of coastal flooding. Subsequently, Dudzai's track curved southward and then southeastward, and on 21 January, it passed south of the 30th parallel south, reaching colder waters and becoming extratropical.Moderate Tropical Storm Ewetse
On 20 January, MFR started monitoring a non-tropical low pressure area along a frontal boundary in the southern Mozambique Channel for possible development. Later that day it was upgraded into a tropical depression. A few hours after that, it was upgraded to Moderate tropical storm, thus receiving the name Ewetse. The storm made landfall near Itampolo shortly after 6:00 UTC on the 21st and weakened rapidly over the mountainous terrain as it moved north. The RSMC La Réunion issued its final bulletin at 12:00 UTC.In Mozambique, although the storm’s centre remained offshore, Ewetse’s outer bands exacerbated a severe humanitarian crisis. The country was already under a national red alert due to weeks of torrential rain that had flooded the Limpopo and Incomati river basins. The storm generated a storm surge of 0.7 m near Ambanhe and brought additional heavy rainfall to the Gaza and Inhambane provinces, where over 600,000 people had already been affected by flooding.
In Madagascar, Ewetse primarily impacted the Toliara Province. While wind damage was limited, the system delivered significant rainfall, with totals exceeding 150 mm in local areas. These rains triggered flash flooding in the southern districts, though they were also noted for providing some relief to regions that had been suffering from prolonged drought. No fatalities were directly attributed to the storm's landfall, but local authorities remained on high alert as the system moved through areas with high vulnerability and poor drainage infrastructure.
Tropical Cyclone Fytia
On 28 January, Météo-France began tracking an area of low pressure, designated as Zone of Disturbed Weather 09, located in the Mozambique Channel. The system formed along a convergence zone between the Comoros and the northwest coast of Madagascar over very warm waters with light wind shear. The disturbance was relatively shallow with a disorganized cloud pattern, a peak 10-minute sustained winds of 45 km/h and a minimum central pressure of 1009 hPa. It was expected to turn toward Madagascar. On January 30, 09 was upgraded to a moderate tropical storm, giving it the name Fytia. Fytia later went through rapid intensification, becoming a tropical cyclone after 12 hours. The cyclone reached a peak intensity of and as it made landfall near Soalala around 01:30–02:00 UTC on 31 January. The system became the strongest cyclone to make landfall in Mahajanga province since Andry in 1983, equal to Belna in 2019.Seven people were killed and five injured as Fytia crossed Madagascar.
Other systems
- Cyclone Jenna crossed into the basin from the Australian region on 8 January as a residual depression, according to MFR. However it weakened quickly and was downgraded to a remnant low on the same day. MFR would then not issue specific bulletins for it.
- On 27 January, Météo-France began monitoring a broad area of low pressure situated to the east of Madagascar, designating it as Zone of Disturbed Weather 08. The disturbance brought increased cloudiness and scattered squalls to parts of Madagascar and the Mascarenes as it continued to be monitored for further organisation. It dissipated over the water on 28 January, merging with a monsoon trough.
Storm names
Within the South-West Indian Ocean, tropical depressions and subtropical depressions that are judged to have 10-minute sustained windspeeds of 65 km/h by the Regional Specialized Meteorological Centre on Réunion island, France are usually assigned a name. However, it is the Sub-Regional Tropical Cyclone Advisory Centres in Mauritius and Madagascar who name the systems. The Sub-Regional Tropical Cyclone Advisory Centre in Mauritius names a storm if it intensifies into a moderate tropical storm between 55°E and 90°E. If instead a cyclone intensifies into a moderate tropical storm between 30°E and 55°E then the Sub-Regional Tropical Cyclone Advisory Centre in Madagascar assigns the appropriate name to the storm. Storm names are taken from three pre-determined lists of names, which rotate on a triennial basis, with any names that have been used automatically removed. New names this season are: Awo, Blossom, Chenge, Dudzai, Ewetse, and Fytia, which replaced Ashley, Balita, Cheneso, Dingani, Enala, and Fabien during the 2022–23 season.If a tropical cyclone crosses 90°E into the South-West Indian basin from the Australian region basin, it will retain the name assigned to it by the Australian Bureau of Meteorology. The following storms were named in this manner.
- Grant