October 2023 Tropical Cyclones Report

Summary

Fifteen named storms occurred across the globe in October, which was above the 1991-2020 average of 12. Nine of those reached tropical cyclone strength (≥74 mph), and seven reached major tropical cyclone strength (≥111 mph). Super Typhoon Bolaven in the West Pacific and Hurricane Otis in the East Pacific both reached category 5 strength (≥157 mph). The global accumulated cyclone energy (ACE: an integrated metric of the strength, frequency, and duration of tropical storms) was about 34% above the 1991-2020 average for October.

The Atlantic had four name storms in October, including two that formed in September. Tammy was the only hurricane, and it did not become a major hurricane. Philippe and Tammy both affected the Leeward islands during September. The ACE for the Atlantic was near its 1991-2020 average in October, and it was about 30% above average for January-October.

The East Pacific had five named storms, including three major hurricanes. The ACE was about twice its 1991-2020 average in October, and about 20% above average for January-October. Four of the five East Pacific named storms during October made landfall in Mexico. Both Lidia and Otis rapidly intensified in the hours leading up to their landfalls. Otis was the strongest hurricane to make landfall along Mexico's west coast, and Lidia was the fourth strongest. Otis caused catastrophic damage to Acapulco City.

Three named storms were active in the West Pacific during October, including two major typhoons. The West Pacific ACE was near its 1991-2020 averages for both October and January-October. Bolaven reached category 5 strength norther of the Northern Mariana Islands. Koinu brought heavy rainfall and strong winds to southern Taiwan before its remnants affected Hong Kong and southern China.

Two named storms occurred in the Indian Ocean in October: Major Cyclone Tej and Cyclone Hamoon. Within a day of each other, Hamoon made landfall near Bangladesh from the Bay of Bengal and Tej made landfall in Yemen from the Arabian Sea. Both storms brought heavy rain and strong winds to their respective regions. The North Indian Ocean ACE was more than twice its 1991-2020 average for October and about 3.5 times its average for January-October.

The only Southern Hemisphere storm in October was Major Cyclone Lola, which caused significant damage to Vanuatu in the Southwest Pacific. Lola was the third storm to affect Vanuatu in 2023, following Judy and Kevin in March.

North Atlantic

October 2023 North Atlantic Tropical Cyclones

Name	Maximum CategoryMax Cat	Dates >39 mph	Maximum Sustained Winds	Minimum Central Pressure
Philippe	TS	September 23-October 6Sep 23-Oct 6	50 mph	998 mb
Rina	TS	September 28-October 1Sep 28-Oct 1	50 mph†	999 mb†
Sean	TS	October 11Oct 11-14	45 mph	1004 mb
Tammy	2	October 18Oct 18-29	105 mph	965 mb
†Value occurred in September

North Atlantic Tropical Cyclone October Counts

Storm Type	Count	1991-2020 Mean	1981-2023 Rank*	1851-2023 Record
Tropical Storm Winds ≥ 39 mph (34 kts)	4	3.2	8th (tied with 7 other Octobers)	9 (1950)
Hurricane Winds ≥ 74 mph (64 kts)	1	1.7	18th (tied with 16 other Octobers)	5 (1870, 1878, 1950, 2010)
Major Hurricane Winds ≥ 111 mph (96 kts)	0	0.8 (8 in 10 Octobers)	20th (tied with 23 other Octobers)	3 (2020)
Accumulated Cyclone Energy ACE×10⁴ kt²	21.0	21.4	19th	87.8 (1878)

North Atlantic Tropical Cyclone Season Counts January-October 2023

Storm Type	Count	1991-2020 Mean	1981-2023 Rank*	1851-2023 Record
Tropical Storm Winds ≥ 39 mph (34 kts)	20	13.5	4th	27 (2020)
Hurricane Winds ≥ 74 mph (64 kts)	7	6.6	13th (tied with 6 other seasons)	14 (2005)
Major Hurricane Winds ≥ 111 mph (96 kts)	3	3.0	12th (tied with 8 other seasons)	7 (2005)
Accumulated Cyclone Energy ACE×10⁴ kt²	144.1	115.6	11th	252.6 (1933)

East Pacific

October 2023 East Pacific Tropical Cyclones

Name	Maximum CategoryMax Cat	Dates >39 mph	Maximum Sustained Winds	Minimum Central Pressure
Lidia	4	October 3Oct 3-11	140 mph	942 mb
Max	TS	October 9Oct 9-10	65 mph	991 mb
Norma	4	October 17Oct 17-23	130 mph	941 mb
Otis	5	October 22Oct 22-25	165 mph	923 mb
Pilar	TS	October 30-November 5Oct 30-Nov 5	60 mph‡	996 mb‡
‡Value occurred in November

East Pacific Tropical Cyclone October Counts

Storm Type	Count	1991-2020 Mean	1981-2023 Rank*	1949-2023 Record
Tropical Storm Winds ≥ 39 mph (34 kts)	5	2.8	3rd (tied with 2 other Octobers)	6 (1992, 2018)
Hurricane Winds ≥ 74 mph (64 kts)	3	1.3	1st (tied with 8 other Octobers)	3 (11 Octobers)
Major Hurricane Winds ≥ 111 mph (96 kts)	3	0.7 (7 in 10 Octobers)	1st (tied with 3 other Octobers)	3 (1983, 1992, 2018, 2023)
Accumulated Cyclone Energy ACE×10⁴ kt²	36.8	18.2	8th	78.0 (2018)

East Pacific Tropical Cyclone Season Counts January-October 2023

Storm Type	Count	1991-2020 Mean	1981-2023 Rank*	1949-2023 Record
Tropical Storm Winds ≥ 39 mph (34 kts)	16	16.4	25th (tied with 3 other seasons)	27 (1992)
Hurricane Winds ≥ 74 mph (64 kts)	10	8.6	13th (tied with 4 other seasons)	16 (1990, 1992)
Major Hurricane Winds ≥ 111 mph (96 kts)	8	4.6	6th (tied with 2 other seasons)	10 (1992, 2015, 2018)
Accumulated Cyclone Energy ACE×10⁴ kt²	161.4	130.1	14th	315.3 (2018)

West Pacific

October 2023 West Pacific Tropical Cyclones

Name	Maximum CategoryMax Cat	Dates >39 mph	Maximum Sustained Winds	Minimum Central Pressure
Koinu	4	September 30-October 9Sep 30-Oct 9	135 mph	940 mb
Bolaven	5	October 7Oct 7-14	175 mph	903 mb
Sanba	TS	October 18Oct 18-20	45 mph	1001 mb

West Pacific Tropical Cyclone October Counts

Storm Type	Count	1991-2020 Mean	1981-2023 Rank*	1945-2023 Record
Tropical Storm Winds ≥ 39 mph (34 kts)	3	4.2	27th (tied with 12 other Octobers)	9 (1984, 2013)
Typhoon Winds ≥ 74 mph (64 kts)	2	3.2	30th (tied with 10 other Octobers)	7 (1992, 2013)
Major Typhoon Winds ≥ 111 mph (96 kts)	2	2.1	12th (tied with 17 other Octobers)	5 (1962, 2013)
Accumulated Cyclone Energy ACE×10⁴ kt²	57.9	58.1	21st	127.6 (1992)

West Pacific Tropical Cyclone Season Counts January-October 2023

Storm Type	Count	1991-2020 Mean	1981-2023 Rank*	1945-2023 Record
Tropical Storm Winds ≥ 39 mph (34 kts)	16	22.6	41st	32 (1964, 1971, 1994)
Typhoon Winds ≥ 74 mph (64 kts)	12	14.2	27th (tied with 4 other seasons)	23 (1971)
Major Typhoon Winds ≥ 111 mph (96 kts)	8	8.3	18th (tied with 4 other seasons)	14 (1965, 2015)
Accumulated Cyclone Energy ACE×10⁴ kt²	266.7	256.2	14th	471.1 (1997)

North Indian

October 2023 North Indian Tropical Cyclones

Name	Maximum CategoryMax Cat	Dates >39 mph	Maximum Sustained Winds	Minimum Central Pressure
Tej	3	October 20Oct 20-24	125 mph	956 mb
Hamoon	1	October 23Oct 23-25	90 mph	978 mb

North Indian Tropical Cyclone October Counts

Storm Type	Count	1991-2020 Mean	1981-2023 Rank*	1972-2023 Record
Tropical Storm Winds ≥ 39 mph (34 kts)	2	1.1	1st (tied with 13 other Octobers)	2 (14 Octobers)
Cyclone Winds ≥ 74 mph (64 kts)	2	0.4 (4 in 10 Octobers)	1st (tied with 3 other Octobers)	2 (1999, 2014, 2018, 2023)
Major Cyclone Winds ≥ 111 mph (96 kts)	1	0.3 (3 in 10 Octobers)	3rd (tied with 5 other Octobers)	2 (1999, 2014)
Accumulated Cyclone Energy ACE×10⁴ kt²	12.5	5.3	7th	26.2 (2019)

North Indian Tropical Cyclone Season Counts January-October 2023

Storm Type	Count	1991-2020 Mean	1981-2023 Rank*	1972-2023 Record
Tropical Storm Winds ≥ 39 mph (34 kts)	6	3.3	1st (tied with 4 other seasons)	6 (5 seasons)
Cyclone Winds ≥ 74 mph (64 kts)	4	1.2	1st (tied with 1 other season)	4 (2019, 2023)
Major Cyclone Winds ≥ 111 mph (96 kts)	3	0.8 (8 in 10 seasons)	1st (tied with 2 other seasons)	3 (1999, 2019, 2023)
Accumulated Cyclone Energy ACE×10⁴ kt²	53.2	15.4	2nd	68.9 (2019)

South Indian

No South Indian Tropical Cyclones occurred during October 2023.

South Indian Tropical Cyclone October Counts

Storm Type	Count	1991-2020 Mean	1981-2023 Rank*	1956-2023 Record
Tropical Storm Winds ≥ 39 mph (34 kts)	0	0.5 (5 in 10 Octobers)	18th (tied with 26 other Octobers)	2 (1993, 2002)
Cyclone Winds ≥ 74 mph (64 kts)	0	0.1 (1 in 10 Octobers)	5th (tied with 39 other Octobers)	1 (1982, 1984, 1997, 2013)
Major Cyclone Winds ≥ 111 mph (96 kts)	0	0.0 (0 in 10 Octobers)	2nd (tied with 42 other Octobers)	1 (2013)
Accumulated Cyclone Energy ACE×10⁴ kt²	0.0	1.0	18th (tied with 26 other Octobers)	12.5 (2013)

South Indian Tropical Cyclone Season Counts July-October 2023

Storm Type	Count	1991-2020 Mean	1981-2023 Rank*	1956-2023 Record
Tropical Storm Winds ≥ 39 mph (34 kts)	0	0.8 (8 in 10 seasons)	25th (tied with 19 other seasons)	3 (1997)
Cyclone Winds ≥ 74 mph (64 kts)	0	0.1 (1 in 10 seasons)	6th (tied with 38 other seasons)	1 (5 seasons)
Major Cyclone Winds ≥ 111 mph (96 kts)	0	0.0 (0 in 10 seasons)	2nd (tied with 42 other seasons)	1 (2013)
Accumulated Cyclone Energy ACE×10⁴ kt²	0.0	1.6	25th (tied with 19 other seasons)	12.5 (2013)

Australia

No Australia Tropical Cyclones occurred during October 2023.

Australia Tropical Cyclone October Counts

Storm Type	Count	1991-2020 Mean	1981-2023 Rank*	1956-2023 Record
Tropical Storm Winds ≥ 39 mph (34 kts)	0	0.1 (1 in 10 Octobers)	6th (tied with 38 other Octobers)	1 (5 Octobers)
Tropical Cyclone Winds ≥ 74 mph (64 kts)	0	0.0 (0 in 10 Octobers)	2nd (tied with 42 other Octobers)	1 (1984)
Major Tropical Cyclone Winds ≥ 111 mph (96 kts)	0	0.0 (0 in 10 Octobers)	1st (tied with 43 other Octobers)	0
Accumulated Cyclone Energy ACE×10⁴ kt²	0.0	0.2 (2 in 10 Octobers)	6th (tied with 38 other Octobers)	2.2 (1984)

Australia Tropical Cyclone Season Counts July-October 2023

Storm Type	Count	1991-2020 Mean	1981-2023 Rank*	1956-2023 Record
Tropical Storm Winds ≥ 39 mph (34 kts)	0	0.3 (3 in 10 seasons)	12th (tied with 32 other seasons)	2 (1997)
Tropical Cyclone Winds ≥ 74 mph (64 kts)	0	0.0 (0 in 10 seasons)	2nd (tied with 42 other seasons)	1 (1984)
Major Tropical Cyclone Winds ≥ 111 mph (96 kts)	0	0.0 (0 in 10 seasons)	1st (tied with 43 other seasons)	0
Accumulated Cyclone Energy ACE×10⁴ kt²	0.0	0.3 (3 in 10 seasons)	12th (tied with 32 other seasons)	2.2 (1984)

Southwest Pacific

October 2023 Southwest Pacific Tropical Cyclones

Name	Maximum CategoryMax Cat	Dates >39 mph	Maximum Sustained Winds	Minimum Central Pressure
Lola	4	October 21Oct 21-25	135 mph	941 mb

Southwest Pacific Tropical Cyclone October Counts

Storm Type	Count	1991-2020 Mean	1981-2023 Rank*	1956-2023 Record
Tropical Storm Winds ≥ 39 mph (34 kts)	1	0.2 (2 in 10 Octobers)	2nd (tied with 3 other Octobers)	3 (1998)
Tropical Cyclone Winds ≥ 74 mph (64 kts)	1	0.0 (0 in 10 Octobers)	1st (tied with 1 other October)	1 (2007, 2024)
Major Tropical Cyclone Winds ≥ 111 mph (96 kts)	1	0.0 (0 in 10 Octobers)	1st (tied with 1 other October)	1 (2007, 2024)
Accumulated Cyclone Energy ACE×10⁴ kt²	12.4	0.5 (5 in 10 Octobers)	1st	12.4‖ (2024)
‖Previous record 9.6 (2007)

Southwest Pacific Tropical Cyclone Season Counts July-October 2023

Storm Type	Count	1991-2020 Mean	1981-2023 Rank*	1956-2023 Record
Tropical Storm Winds ≥ 39 mph (34 kts)	1	0.3 (3 in 10 seasons)	3rd (tied with 4 other seasons)	3 (1998)
Tropical Cyclone Winds ≥ 74 mph (64 kts)	1	0.0 (0 in 10 seasons)	1st (tied with 1 other season)	1 (2007, 2024)
Major Tropical Cyclone Winds ≥ 111 mph (96 kts)	1	0.0 (0 in 10 seasons)	1st (tied with 1 other season)	1 (2007, 2024)
Accumulated Cyclone Energy ACE×10⁴ kt²	12.4	0.6 (6 in 10 seasons)	1st	12.4‖ (2024)
‖Previous record 9.6 (2007)

Global

October 2023 Global Tropical Cyclones

Name	Maximum CategoryMax Cat	Dates >39 mph	Maximum Sustained Winds	Minimum Central Pressure
Philippe	TS	September 23-October 6Sep 23-Oct 6	50 mph	998 mb
Rina	TS	September 28-October 1Sep 28-Oct 1	50 mph†	999 mb†
Koinu	4	September 30-October 9Sep 30-Oct 9	135 mph	940 mb
Lidia	4	October 3Oct 3-11	140 mph	942 mb
Bolaven	5	October 7Oct 7-14	175 mph	903 mb
Max	TS	October 9Oct 9-10	65 mph	991 mb
Sean	TS	October 11Oct 11-14	45 mph	1004 mb
Norma	4	October 17Oct 17-23	130 mph	941 mb
Tammy	2	October 18Oct 18-29	105 mph	965 mb
Sanba	TS	October 18Oct 18-20	45 mph	1001 mb
Tej	3	October 20Oct 20-24	125 mph	956 mb
Lola	4	October 21Oct 21-25	135 mph	941 mb
Otis	5	October 22Oct 22-25	165 mph	923 mb
Hamoon	1	October 23Oct 23-25	90 mph	978 mb
Pilar	TS	October 30-November 5Oct 30-Nov 5	60 mph‡	996 mb‡
†Value occurred in September
‡Value occurred in November

Global Tropical Cyclone October Counts

Storm Type	Count	1991-2020 Mean	1981-2023 Rank*	1972-2023 Record
Tropical Storm Winds ≥ 39 mph (34 kts)	15	12.0	7th (tied with 1 other October)	20 (1992)
Tropical Cyclone Winds ≥ 74 mph (64 kts)	9	6.7	4th (tied with 4 other Octobers)	11 (1992)
Major Tropical Cyclone Winds ≥ 111 mph (96 kts)	7	4.0	1st (tied with 4 other Octobers)	7 (5 Octobers)
Accumulated Cyclone Energy ACE×10⁴ kt²	140.6	104.8	9th	206.3 (2018)

Global Tropical Cyclone Season Counts January-October 2023

Storm Type	Count	1991-2020 Mean	1981-2023 Rank*	1972-2023 Record
Tropical Storm Winds ≥ 39 mph (34 kts)	71	76.0	29th (tied with 2 other seasons)	92 (2018)
Tropical Cyclone Winds ≥ 74 mph (64 kts)	43	41.5	12th (tied with 3 other seasons)	53 (1990)
Major Tropical Cyclone Winds ≥ 111 mph (96 kts)	28	22.6	3rd (tied with 1 other season)	35 (2015)
Accumulated Cyclone Energy ACE×10⁴ kt²	816.1	686.4	8th	1,012.3 (2018)

Data Description

The data in this report are derived from NCEI's IBTrACS dataset (Knapp et al. 2010; Schreck et al. 2014). IBTrACS tropical cyclone track and intensity data from agencies and sources around the globe. In this report, data from NOAA's National Hurricane Center (NHC) are used for the North Atlantic and East Pacific. The other basin's use data from the U.S. Military's Joint Typhoon Warning Center (JTWC).

Historical values use the "best track" data that have been analyzed by forecasters after the season using all available data. Operational procedures and observing systems have changed with time and between regions, which makes these data heterogeneous. Intensity data are generally the most reliable since the early 1970s in the Atlantic (Landsea and Franklin 2013) and since the mid-1980s in other regions (Chu et al. 2002). The number of short-lived storms (≤2 days) has also increased since around 2000 due to improvements in observations and analysis techniques (Landsea et al. 2010).

Values for the current year are provisional values from the operational forecast advisories. IBTrACS obtains these from NCEP's TC Vitals, the NCAR Tropical Cyclone Guidance Project, and NHC provisional data. These values are subject to change during the post-season best track analysis. They also only include 6-hourly storm fixes, which means they may miss special advisories at landfall, peak intensity, etc.

The tropical cyclone seasons in the Southern Hemisphere begin in July and end in June, while the Northern Hemisphere seasons are counted from January to December. Storms are counted in all basins, months, and years in which they occur, which means some storms may appear more than once. However, the global totals only include each storm one time.

References

• Chu, J.-H., C. R. Sampson, A. S. Levine, and E. Fukada, 2002: The joint typhoon warning center tropical cyclone best-tracks, 1945–2000. Naval Research Laboratory, Reference Number NRL/MR/7540-02-16, 22 pp., https://www.metoc.navy.mil/jtwc/products/best-tracks/tc-bt-report.html.
• Knapp, K. R., M. C. Kruk, D. H. Levinson, H. J. Diamond, and C. J. Neumann, 2010: The International Best Track Archive for Climate Stewardship (IBTrACS). Bull. Amer. Meteor. Soc., 91, 363–376, https://doi.org/10.1175/2009BAMS2755.1.
• Landsea, C. W., and J. L. Franklin, 2013: Atlantic Hurricane database uncertainty and presentation of a new database format. Mon. Wea. Rev., 141, 3576–3592, https://doi.org/10.1175/MWR-D-12-00254.1.
• ——, G. A. Vecchi, L. Bengtsson, and T. R. Knutson, 2010: Impact of duration thresholds on Atlantic tropical cyclone counts. J. Climate, 23, 2508–2519, https://doi.org/10.1175/2009JCLI3034.1.
• Schreck, C. J., K. R. Knapp, and J. P. Kossin, 2014: The Impact of Best Track Discrepancies on Global Tropical Cyclone Climatologies using IBTrACS. Mon. Wea. Rev., 142, 3881–3899, https://doi.org/10.1175/MWR-D-14-00021.1.