The 2025–26 South-West Indian Ocean cyclone season was an active and very destructive South-West Indian Ocean cyclone season. Although only 2 storms did measurable damage, it was the third costliest on record, mainly due to Cyclone Gezani, which itself became the costliest cyclone in Madagascar’s history. It officially began on 15 November 2025, and ended on 30 April 2026, with the exception for Mauritius and the Seychelles, for which it ended 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, also 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.
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Seasonal forecasts RecordModerateTropical StormTropical Cyclone Average105 Record high15 (2018–19)11 (2018–19) Record low3 (1982–83)0 (1982–83) ForecastcenterSystems Météo-France10–145–8 Mauritius Meteorological Services11–13 colspan=3 ForecastcenterChance ofbelow/near/above average Météo-France10%40%50%Sources:
Seasonal summary
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 after rapidly intensifying into an Intense Tropical Cyclone in the central part of the basin, far from land.
Peak season activity
On 8 January, Cyclone Jenna crossed the 90th meridian east from the Australian region into the South-West Indian Ocean basin. Météo-France did not monitor the system, labeling it as a "residual depression". The Joint Typhoon Warning Center continued to monitor the system as a tropical storm for a short time before its degeneration into a remnant low on 9 January. On 10 January, Cyclone Dudzai developed in the central part of the basin, 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. Dudzai then weakened quickly immediately after intensifying, before accelerating westward and quickly intensified once again, before becoming extratropical as it recurved away from land. While it was dissipating, on 20 January, Ewetse formed and quickly made landfall in southwestern Madagascar as a Moderate Tropical Storm the next day. Six days later, Zone of Disturbed Weather 08 formed but quickly dissipated the following day as it merged into a monsoon trough. Fytia formed the following day and rapidly intensified before making landfall in northwestern Madagascar as a high–end Tropical Cyclone on 31 January. After crossing Madagascar, it dissipated south of Réunion. Twelve were killed in Madagascar by the storm. On 8 February, Gezani formed. It slowly strengthened and made landfall in Madagascar as an Intense Tropical Cyclone, causing over 63 casualties. It later impacted Mozambique as a Tropical Cyclone. On February 24, Cyclone Horacio formed and became a Category 5 tropical cyclone on the SSHWS scale, the first to do so in the Southern Hemisphere since Errol in April 2025, and the first globally in 2026.
Late season activity Tropical Depression 12 formed on March 12 but it quickly weakened and dissipated the following day. Cyclone Indusa formed on April 1 and it rapidly intensified into a tropical cyclone on April 4. An extratropical cyclone formed on April 26, it later developed subtropical characteristics, and was named Juluka the following day.
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 and on the northeast of Madagascar. 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. Awo struggled to intensify due to persistent easterly wind shear and limited upper‑level outflow, which prevented further organization. Throughout its lifespan, the system remained poorly structured, with most convection displaced away from the low‑level center. Increasing shear and dry air intrusion caused Awo to weaken steadily before dissipating.
Moderate Tropical Storm Blossom
Meteo-France Réunion began monitoring a disturbance on 7 September. At 10:00 a.m. (0600Z) 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. Chenge dissipated on 25 October. After dissipation, the remnants of Chenge were absorbed into a broader monsoonal flow over East Africa.
As the storm passed north of Madagascar, only minor effects such as increased swells and occasional rainbands were observed over nearby islands, including the Glorioso Islands and Juan de Nova. No significant damage was reported and producing scattered rainfall over parts of Kenya and Tanzania without causing notable impacts.
Intense Tropical Cyclone Grant
On 27 December, Grant entered the basin from the Australian Region at 10:00 RET (06:00 UTC) 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 (JTWC) 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 (RSMC) 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