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An off-season South-West Indian Ocean tropical cyclone is a tropical cyclone that exists in the South-West Indian Ocean basin outside of the official tropical cyclone season. The World Meteorological Organization currently defines the season as occurring between November 15 and April 30, of the following year, with the exception for Mauritius and the Seychelles, for which it lasts through May 15 rather than April 30. As of 2024, there have been at least 113 tropical cyclones known to have occurred off-season. Cumulatively, at least 165 deaths occurred due to the storms, and the most recent off-season storm was Moderate Tropical Storm Blossom in September 2025.
The wind speeds listed are maximum ten-minute average sustained winds, while the pressure is the minimum barometric pressure, both of which are estimates taken from the archives of either Météo-France, the Australian Bureau of Meteorology, the Fiji Meteorological Service, and New Zealand's MetService. If there are no known estimates of either the winds or pressure then the system is listed as "Not specified" under winds or pressure, if there is no known estimated winds or pressure. For deaths and damages "None" indicates that there were no reports of fatalities, although such storms may have impacted land. The damage totals are the United States dollar of the year of the storm.
Name | Dates | Peak intensity | Areas affected | Damage (USD) | Deaths | Refs | ||
---|---|---|---|---|---|---|---|---|
Category | Wind speed | Pressure | ||||||
Unnamed | 1-7 November, 1851 | Not specified | Not specified | Not specified | None | None | None | [1] |
Unnamed | 31 October – 5 November, 1854 | Not specified | Not specified | Not specified | None | None | None | [2] |
Unnamed | 11-17 May, 1855 | Not specified | Not specified | Not specified | None | None | None | [3] |
Unnamed | 31 October – 3 November, 1858 | Not specified | Not specified | Not specified | None | None | None | [4] |
Unnamed | 31 May – 3 June, 1859 | Not specified | Not specified | Not specified | None | None | None | [5] |
Unnamed | 11-15 June, 1859 | Not specified | Not specified | Not specified | None | None | None | [6] |
Unnamed | 1-7 May, 1860 | Not specified | Not specified | Not specified | None | None | None | [7] |
Unnamed | 11-15 November, 1861 | Not specified | Not specified | Not specified | None | None | None | [8] |
Unnamed | 11-14 October, 1862 | Not specified | Not specified | Not specified | None | None | None | [9] |
Unnamed | 11-16 November, 1862 | Not specified | Not specified | Not specified | None | None | None | [10] |
Unnamed | 21-30 May, 1863 | Not specified | Not specified | Not specified | None | None | None | [11] |
Unnamed | 31 October – 3 November, 1863 | Not specified | Not specified | Not specified | None | None | None | [12] |
Unnamed | 1-5 November, 1866 | Not specified | Not specified | Not specified | None | None | None | [13] |
Unnamed | 1-7 May, 1867 | Not specified | Not specified | Not specified | None | None | None | [14] |
Unnamed | 11-17 November, 1868 | Not specified | Not specified | Not specified | None | None | None | [15] |
Unnamed | 1-8 November, 1869 | Not specified | Not specified | Not specified | None | None | None | [16] |
Unnamed | 1-5 May, 1872 | Not specified | Not specified | Not specified | None | None | None | [17] |
Unnamed | 1-6 October, 1872 | Not specified | Not specified | Not specified | None | None | None | [18] |
Unnamed | 31 October – 4 November, 1872 | Not specified | Not specified | Not specified | None | None | None | [19] |
Unnamed | 11-17 May, 1877 | Not specified | Not specified | Not specified | None | None | None | [20] |
Unnamed | 9-14 November, 1884 | Tropical storm | Not specified | Not specified | None | None | None | [21] |
Unnamed | 11-18 May, 1885 | Not specified | Not specified | Not specified | None | None | None | [22] |
Unnamed | 9-12 November, 1899 | Tropical storm | Not specified | Not specified | None | None | None | [23] |
Unnamed | 9-13 November, 1902 | Tropical storm | Not specified | Not specified | None | None | None | [24] |
Unnamed | 9-10 May, 1907 | Tropical storm | Not specified | Not specified | None | None | None | [25] |
Unnamed | 9-15 May, 1912 | Tropical depression | 45 km/h (30 mph) | Not Specified | None | None | None | [26] |
Unnamed | 23-29 May, 1916 | Moderate tropical storm | 65 km/h (40 mph) | Not Specified | Mauritius | None | None | [27] |
Unnamed | 9-12 November, 1921 | Tropical depression | 45 km/h (30 mph) | Not Specified | None | None | None | [28] |
Unnamed | 9-14 November, 1927 | Tropical depression | 45 km/h (30 mph) | Not Specified | None | None | None | [29] |
Unnamed | 7-12 May, 1929 | Moderate tropical storm | 65 km/h (40 mph) | Not Specified | Mauritius | None | None | [30] |
Unnamed | 9-13 September, 1929 | Tropical depression | 45 km/h (30 mph) | Not Specified | None | None | None | [31] |
Unnamed | 31 October – 5 November, 1934 | Tropical depression | 45 km/h (30 mph) | Not Specified | None | None | None | [32] |
Unnamed | 9-14 November, 1934 | Tropical depression | 45 km/h (30 mph) | Not Specified | None | None | None | [33] |
Unnamed | 14-19 November, 1934 | Tropical depression | 45 km/h (30 mph) | Not Specified | Madagascar | None | None | [34] |
Unnamed | 9-17 May, 1940 | Tropical depression | 45 km/h (30 mph) | Not Specified | None | None | None | [35] |
Unnamed | 15-26 September, 1944 | Tropical depression | 45 km/h (30 mph) | Not Specified | Mauritius | None | None | [36] |
Unnamed | 22-31 October, 1944 | Moderate tropical storm | 65 km/h (40 mph) | Not Specified | None | None | None | [37] |
Unnamed | 2-6 June, 1949 | Moderate tropical storm | 65 km/h (40 mph) | Not Specified | Mauritius | None | None | [38] |
Unnamed | 15-21 October, 1950 | Moderate tropical storm | 65 km/h (40 mph) | Not Specified | None | None | None | [39] |
Unnamed | 10-28 May, 1952 | Moderate tropical storm | 65 km/h (40 mph) | Not Specified | Madagascar | None | None | [40] |
Unnamed | 20-29 July, 1954 | Moderate tropical storm | 65 km/h (40 mph) | Not Specified | None | None | None | [41] |
Unnamed | 11-23 October, 1954 | Moderate tropical storm | 65 km/h (40 mph) | Not Specified | None | None | None | [42] |
Unnamed | 4-8 November, 1954 | Tropical depression | 45 km/h (30 mph) | Not Specified | None | None | None | [43] |
Unnamed | 29 October – 4 November, 1959 | Tropical depression | 55 km/h (35 mph) | Not Specified | Madagascar | None | None | [44] |
1960s
Name | Dates | Peak intensity | Areas affected | Damage (USD) | Deaths | Refs | ||
---|---|---|---|---|---|---|---|---|
Category | Wind speed | Pressure | ||||||
Anna | 11-14 November, 1960 | Tropical storm | 65 km/h (40 mph) | Not Specified | None | None | None | [45] |
Amy | 6-16 October, 1962 | Moderate tropical storm | 75 km/h (45 mph) | Not Specified | None | None | None | [46] |
Jose | 29 April – 3 May, 1964 | Moderate tropical storm | 75 km/h (45 mph) | Not Specified | None | None | None | [47] |
Karen | 2-10 May, 1964 | Moderate tropical storm | 85 km/h (50 mph) | Not Specified | None | None | None | [48] |
Rose | 27 April – 6 May, 1965 | Moderate tropical storm | 75 km/h (45 mph) | Not Specified | Réunion | None | None | [49] |
Anne | 15-15 August, 1965 | Tropical disturbance | 35 km/h (25 mph) | Not Specified | None | None | None | [50] |
Brenda | 16-18 August, 1965 | Tropical disturbance | 45 km/h (30 mph) | Not Specified | None | None | None | [51] |
Lily | 22 April – 1 May, 1966 | Tropical depression | 55 km/h (35 mph) | Not Specified | None | None | None | [52] |
Angela | 28 September – 6 October, 1966 | Moderate tropical storm | 65 km/h (40 mph) | Not Specified | None | None | None | [53] |
Kathy | 12-21 May, 1967 | Tropical disturbance | 45 km/h (30 mph) | Not Specified | None | None | None | [54] |
Anita | 30 October – 2 November, 1967 | Moderate tropical storm | 65 km/h (40 mph) | Not Specified | None | None | None | [55] |
Annie | 28 October – 4 November, 1968 | Severe tropical storm | 100 km/h (65 mph) | Not Specified | None | None | None | [56] |
Aline | 19-22 August, 1969 | Severe tropical storm | 100 km/h (65 mph) | Not Specified | None | None | None | [57] |
Blanche | 7-15 October, 1969 | Tropical cyclone | 130 km/h (80 mph) | Not Specified | None | None | None | [58] |
Corrine | 11-21 November, 1969 | Moderate tropical storm | 85 km/h (50 mph) | Not Specified | Comoros, Mozambique | Unknown | 26 | [59] |
Name | Dates | Peak intensity | Areas affected | Damage (USD) | Deaths | Refs | ||
---|---|---|---|---|---|---|---|---|
Category | Wind speed | Pressure | ||||||
Andree | 16-19 September, 1970 | Tropical disturbance | 45 km/h (30 mph) | Not Specified | None | None | None | |
Betsy | 1–9 October 1970 | Moderate tropical storm | 65 km/h (40 mph) | Not Specified | None | None | None | [60] |
Andrea–Claudine | 31 October – 13 November 1970 | Moderate tropical storm | 65 km/h (40 mph) | 970 hPa (28.64 inHg) | None | None | None | [61] |
Odette | 9–16 July 1971 | Moderate tropical storm | 65 km/h (40 mph) | Not Specified | None | None | None | [62] |
Marcelle | 1–3 May 1973 | Tropical cyclone | 130 km/h (80 mph) | 972 hPa (28.70 inHg) | Australia | Unknown | None | [63] |
Alice | 14–24 September 1973 | Moderate tropical storm | 75 km/h (45 mph) | 1,000 hPa (29.53 inHg) | None | None | None | [64] |
Bernadette | 16–28 October 1973 | Tropical cyclone | 150 km/h (90 mph) | 985 hPa (29.09 inHg) | Madagascar | Unknown | None | [65] |
Agathe | 3–14 October 1976 | Moderate tropical storm | 65 km/h (40 mph) | 995 hPa (29.38 inHg) | None | None | None | [66] |
Name | Dates | Peak intensity | Areas affected | Damage (USD) | Deaths | Refs | ||
---|---|---|---|---|---|---|---|---|
Category | Wind speed | Pressure | ||||||
Bessi–Armelle | 1–20 November 1981 | Severe tropical storm | 100 km/h (65 mph) | 976 hPa (28.82 inHg) | None | None | None | [67] |
Unnamed | 4–6 July 1982 | Tropical depression | 55 km/h (35 mph) | Not Specified | None | None | None | [68] |
Arilisy | 27–30 October 1982 | Tropical depression | 45 km/h (30 mph) | 997 hPa (29.44 inHg) | None | None | None | [69] |
Fely | 22–24 June 1983 | Tropical depression | 35 km/h (25 mph) | 1,003 hPa (29.62 inHg) | None | None | None | [70] |
Unnamed | 9–17 November 1984 | Moderate tropical storm | 85 km/h (50 mph) | 987 hPa (29.15 inHg) | None | None | None | [71] |
Unnamed | 22–29 September 1985 | Moderate tropical storm | 75 km/h (45 mph) | Not Specified | None | None | None | [72] |
Billy–Lila | 9–10 May 1986 | Tropical cyclone | 140 km/h (85 mph) | 950 hPa (28.05 inHg) | None | None | None | [73] |
Unnamed | 31 October – 9 November 1987 | Severe tropical storm | 100 km/h (65 mph) | Not Specified | None | None | None | [74] |
Iarisena | 6–14 May 1988 | Moderate tropical storm | 65 km/h (40 mph) | 991 hPa (29.26 inHg) | None | None | None | [75] |
Adelinina | 1–8 November 1988 | Moderate tropical storm | 85 km/h (50 mph) | 984 hPa (29.06 inHg) | None | None | None | [76] |
Barisaona | 12–23 November 1988 | Tropical cyclone | 140 km/h (85 mph) | 954 hPa (28.17 inHg) | None | None | None | [77] |
Unnamed | 21–27 September 1989 | Tropical depression | 55 km/h (35 mph) | Not Specified | None | None | None | [78] |
Name | Dates | Peak intensity | Areas affected | Damage (USD) | Deaths | Refs | ||
---|---|---|---|---|---|---|---|---|
Category | Wind speed | Pressure | ||||||
Ikonjo | 11–21 May 1990 | Severe tropical storm | 95 km/h (60 mph) | 976 hPa (28.82 inHg) | Seychelles | 1.5 million | None | [79] |
01S | 19–25 September 1990 | Tropical depression | 55 km/h (35 mph) | Not Specified | None | None | None | [80] |
Gritelle | 5–16 June 1991 | Moderate tropical storm | 85 km/h (50 mph) | 984 hPa (29.06 inHg) | None | None | None | [81] |
Aviona | 27 September – 5 October 1992 | Moderate tropical storm | 75 km/h (45 mph) | 988 hPa (29.18 inHg) | None | None | None | [82] |
Babie | 18–21 October 1992 | Moderate tropical storm | 75 km/h (45 mph) | 991 hPa (29.26 inHg) | None | None | None | [83] |
Konita | 2–7 May 1993 | Tropical cyclone | 130 km/h (80 mph) | 955 hPa (28.20 inHg) | None | None | None | [84] |
Antoinette | 17–21 October 1996 | Severe tropical cyclone | 110 km/h (70 mph) | 965 hPa (28.50 inHg) | None | None | None | [85] |
Melanie–Bellamine | 1–11 November 1996 | Intense tropical cyclone | 175 km/h (110 mph) | 925 hPa (27.32 inHg) | None | None | None | [86] |
Name | Dates | Peak intensity | Areas affected | Damage (USD) | Deaths | Refs | ||
---|---|---|---|---|---|---|---|---|
Category | Wind speed | Pressure | ||||||
12S | 20–24 June 2001 | Subtropical depression | 95 km/h (60 mph) | 995 hPa (29.38 inHg) | None | None | None | [87] |
Alex–Andre | 28 October – 8 November 2001 | Severe tropical storm | 95 km/h (60 mph) | 985 hPa (29.09 inHg) | None | None | None | [88] |
Kesiny | 2–11 May 2002 | Tropical cyclone | 130 km/h (80 mph) | 965 hPa (28.50 inHg) | Madagascar | Unknown | 33 | [89] |
01S | 5–8 September 2002 | Moderate tropical storm | 65 km/h (40 mph) | 1,003 hPa (29.62 inHg) | Seychelles | 50,000 | None | [90] |
Atang | 4–13 November 2002 | Tropical depression | 55 km/h (35 mph) | 997 hPa (29.44 inHg) | Madagascar, Mozambique, Tanzania | Unknown | Several | [91] |
Boura | 14–27 November 2002 | Tropical cyclone | 130 km/h (80 mph) | 965 hPa (28.50 inHg) | Mauritius, Réunion | Unknown | None | [92] |
Manou | 2–10 May 2003 | Tropical cyclone | 155 km/h (100 mph) | 950 hPa (28.05 inHg) | Mauritius, Madagascar | Unknown | 89 | [93] |
Abaimba | 28 September – 4 October 2003 | Moderate tropical storm | 85 km/h (50 mph) | 995 hPa (29.38 inHg) | None | None | None | [94] |
Beni | 9–25 November 2003 | Intense tropical cyclone | 175 km/h (110 mph) | 935 hPa (27.61 inHg) | Réunion | Unknown | None | [95] |
Juba | 5–17 May 2004 | Severe tropical storm | 100 km/h (65 mph) | 980 hPa (28.94 inHg) | None | None | None | [96] |
Arola | 6–18 November 2004 | Severe tropical storm | 110 km/h (70 mph) | 978 hPa (28.88 inHg) | None | None | None | [97] |
Asma | 15–24 October 2008 | Moderate tropical storm | 85 km/h (50 mph) | 988 hPa (29.18 inHg) | Madagascar | Unknown | 1 | [98] |
Anja | 13–18 November 2009 | Intense tropical cyclone | 165 km/h (105 mph) | 950 hPa (28.05 inHg) | None | None | None | [99] |
Name | Dates | Peak intensity | Areas affected | Damage (USD) | Deaths | Refs | ||
---|---|---|---|---|---|---|---|---|
Category | Wind speed | Pressure | ||||||
Joël | 26–29 May 2010 | Subtropical depression | 110 km/h (70 mph) | 990 hPa (29.23 inHg) | Mozambique, Madagascar | Unknown | None | [100] |
Kuena | 3–8 June 2012 | Moderate tropical storm | 85 km/h (50 mph) | 994 hPa (29.35 inHg) | None | None | None | [101] |
Anais | 12–19 October 2012 | Intense tropical cyclone | 185 km/h (115 mph) | 945 hPa (27.91 inHg) | None | None | None | [102] |
Abela | 15–19 July 2016 | Severe tropical storm | 95 km/h (60 mph) | 987 hPa (29.15 inHg) | Madagascar | None | None | [103] |
Bransby | 3–6 October 2016 | Subtropical depression | 100 km/h (65 mph) | 987 hPa (29.15 inHg) | None | None | None | [104] |
01S | 14–17 September 2018 | Moderate tropical storm | 75 km/h (45 mph) | 995 hPa (29.38 inHg) | None | None | None | [105] |
Alcide | 5–11 November 2018 | Intense tropical cyclone | 185 km/h (115 mph) | 960 hPa (28.35 inHg) | None | None | None | [106] |
Name | Dates | Peak intensity | Areas affected | Damage (USD) | Deaths | Refs | ||
---|---|---|---|---|---|---|---|---|
Category | Wind speed | Pressure | ||||||
Alicia | 12–17 November 2020 | Tropical cyclone | 130 km/h (80 mph) | 975 hPa (28.79 inHg) | None | None | None | [107] |
Karim | 5–7 May 2022 | Moderate tropical storm | 75 km/h (45 mph) | 994 hPa (29.35 inHg) | None | None | None | [108] |
Ashley | 23–28 September 2022 | Moderate tropical storm | 75 km/h (45 mph) | 1,000 hPa (29.53 inHg) | None | None | None | |
Balita | 3–9 October 2022 | Moderate tropical storm | 65 km/h (40 mph) | 996 hPa (29.41 inHg) | None | None | None | |
Fabien | 12–21 May 2023 | Intense tropical cyclone | 175 km/h (110 mph) | 958 hPa (28.29 inHg) | Diego Garcia | None | 16 | |
Hidaya | 30 April – 4 May 2024 | Tropical cyclone | 140 km/h (85 mph) | 975 hPa (28.79 inHg) | Seychelles, Comoro Islands, Tanzania | None | 1 | |
Ialy | 16–22 May 2024 | Tropical cyclone | 120 km/h (75 mph) | 983 hPa (29.03 inHg) | Seychelles, Madagascar, Tanzania, Kenya, Somalia | None | None | |
01 | 15–17 August 2024 | Tropical depression | 55 km/h (35 mph) | 1,000 hPa (29.53 inHg) | Chagos Archipelago | None | None | |
Ancha | 30 September – 5 October 2024 | Moderate tropical storm | 85 km/h (50 mph) | 992 hPa (29.29 inHg) | None | None | None | |
Bheki | 12–23 November 2024 | Intense tropical cyclone | 195 km/h (120 mph) | 943 hPa (27.85 inHg) | None | None | None | |
01 | 16 July 2025 | Tropical depression | 55 km/h (35 mph) | 1,001 hPa (29.56 inHg) | None | None | None | |
Awo | 7–8 August 2025 | Moderate tropical storm | 65 km/h (40 mph) | 1,000 hPa (29.53 inHg) | Agaléga | None | None | |
Blossom | 9–11 September 2025 | Moderate tropical storm | 65 km/h (40 mph) | 1,001 hPa (29.56 inHg) | None | None | None |