May 2023 Tropical Cyclones Report

Summary

Three named storms occurred across the globe in May. All of those reached major tropical cyclone strength (≥111 mph). This was the first time since March 1978 when all of the named storms across the globe were also major tropical cyclones. Two storms also reached category 5 on the Saffir-Simpson hurricane wind scale.

Three storms is near the 1991-2020 average for named storms in May but above-average for tropical cyclones (≥74 mph). It ties 2008 and 2015 for the most major hurricanes in May. The global accumulated cyclone energy (ACE: an integrated metric of the strength, frequency, and duration of tropical storms) was the highest on record in May and about 10% higher than the previous record set in 2015.

No storms formed in the Atlantic or Eastern Pacific in May. However, the National Hurricane Center retroactively identified a subtropical cyclone from January 2023.

Super Typhoon Mawar was the second named storm of the year for the western Pacific. Activity through May is near normal in terms of the number of named storms, typhoons, and major typhoons. However, the ACE is about twice its 1991-2020 average value in large part to Mawar.

Mawar was just the third category 4 (winds ≥130 mph) typhoon to pass within 100 miles of Guam in the Western Pacific. It was the first major typhoon in that area since Mangkut in 2018. Mawar resulted in heavy rainfall and widespread power outages on the island. After its passage near Guam, Mawar intensified to a category 5 storm. It later recurved and weakened but it still caused minor damage in the Philippines, Taiwan, and flooding in Japan.

The North Indian Ocean's first named storm of 2023 was Cyclone Mocha, which also achieved category 5 strength as it approached landfall in Myanmar. It made landfall as a category 4 cyclone, and the winds, rainfall, and storm surge resulted in hundreds of deaths. The cyclone activity in the Indian Ocean during May was near the 1991-2020 average for named storms but above average for cyclones and major cyclones. The ACE was about twice its average value.

The only named storm in the Southern Hemisphere during May was Cyclone Fabien, which reached category 3 strength as it passed near Diego Garcia in the South Indian Ocean. This was only the third year on record (1997, 2017) with a major cyclone in the Southern Hemisphere during May.

North Atlantic

No North Atlantic Tropical Cyclones occurred during May 2023.

North Atlantic Tropical Cyclone May Counts

Storm Type	Count	1991-2020 Mean	1981-2023 Rank*	1851-2023 Record
Tropical Storm Winds ≥ 39 mph (34 kts)	0	0.3 (3 in 10 Mays)	11th (tied with 32 other Mays)	2 (1887, 2012, 2020)
Hurricane Winds ≥ 74 mph (64 kts)	0	0.0 (0 in 10 Mays)	1st (tied with 42 other Mays)	1 (1889, 1908, 1951, 1970)
Major Hurricane Winds ≥ 111 mph (96 kts)	0	0.0 (0 in 10 Mays)	1st (tied with 42 other Mays)	0
Accumulated Cyclone Energy ACE×10⁴ kt²	0.0	0.4 (4 in 10 Mays)	11th (tied with 32 other Mays)	16.1 (1951)

North Atlantic Tropical Cyclone Season Counts January-May 2023

Storm Type	Count	1991-2020 Mean	1981-2023 Rank*	1851-2023 Record
Tropical Storm Winds ≥ 39 mph (34 kts)	1	0.5 (5 in 10 seasons)	4th (tied with 11 other seasons)	2 (6 seasons)
Hurricane Winds ≥ 74 mph (64 kts)	0	0.0 (0 in 10 seasons)	2nd (tied with 41 other seasons)	2 (1908)
Major Hurricane Winds ≥ 111 mph (96 kts)	0	0.0 (0 in 10 seasons)	1st (tied with 42 other seasons)	0
Accumulated Cyclone Energy ACE×10⁴ kt²	0.0	0.9 (9 in 10 seasons)	15th (tied with 28 other seasons)	21.6 (1951)

East Pacific

No East Pacific Tropical Cyclones occurred during May 2023.

East Pacific Tropical Cyclone May Counts

Storm Type	Count	1991-2020 Mean	1981-2023 Rank*	1949-2023 Record
Tropical Storm Winds ≥ 39 mph (34 kts)	0	0.7 (7 in 10 Mays)	27th (tied with 16 other Mays)	2 (6 Mays)
Hurricane Winds ≥ 74 mph (64 kts)	0	0.3 (3 in 10 Mays)	14th (tied with 29 other Mays)	1 (16 Mays)
Major Hurricane Winds ≥ 111 mph (96 kts)	0	0.2 (2 in 10 Mays)	6th (tied with 37 other Mays)	1 (5 Mays)
Accumulated Cyclone Energy ACE×10⁴ kt²	0.0	3.1	27th (tied with 16 other Mays)	18.6 (2014)

East Pacific Tropical Cyclone Season Counts January-May 2023

Storm Type	Count	1991-2020 Mean	1981-2023 Rank*	1949-2023 Record
Tropical Storm Winds ≥ 39 mph (34 kts)	0	0.8 (8 in 10 seasons)	30th (tied with 13 other seasons)	2 (7 seasons)
Hurricane Winds ≥ 74 mph (64 kts)	0	0.3 (3 in 10 seasons)	16th (tied with 27 other seasons)	1 (18 seasons)
Major Hurricane Winds ≥ 111 mph (96 kts)	0	0.2 (2 in 10 seasons)	7th (tied with 36 other seasons)	1 (6 seasons)
Accumulated Cyclone Energy ACE×10⁴ kt²	0.0	3.8	30th (tied with 13 other seasons)	18.6 (2014)

West Pacific

May 2023 West Pacific Tropical Cyclones

Name	Maximum CategoryMax Cat	Dates >39 mph	Maximum Sustained Winds	Minimum Central Pressure
Mawar	5	May 20-June 3May 20-Jun 3	185 mph	897 mb

West Pacific Tropical Cyclone May Counts

Storm Type	Count	1991-2020 Mean	1981-2023 Rank*	1945-2023 Record
Tropical Storm Winds ≥ 39 mph (34 kts)	1	1.2	14th (tied with 17 other Mays)	6 (1971)
Typhoon Winds ≥ 74 mph (64 kts)	1	0.7 (7 in 10 Mays)	5th (tied with 19 other Mays)	3 (1971, 2008)
Major Typhoon Winds ≥ 111 mph (96 kts)	1	0.5 (5 in 10 Mays)	3rd (tied with 14 other Mays)	2 (1976, 2008, 2015)
Accumulated Cyclone Energy ACE×10⁴ kt²	53.6	13.3	2nd	58.9 (2015)

West Pacific Tropical Cyclone Season Counts January-May 2023

Storm Type	Count	1991-2020 Mean	1981-2023 Rank*	1945-2023 Record
Tropical Storm Winds ≥ 39 mph (34 kts)	2	2.8	21st (tied with 13 other seasons)	9 (1971)
Typhoon Winds ≥ 74 mph (64 kts)	1	1.4	19th (tied with 15 other seasons)	5 (2015)
Major Typhoon Winds ≥ 111 mph (96 kts)	1	0.9 (9 in 10 seasons)	8th (tied with 20 other seasons)	4 (2015)
Accumulated Cyclone Energy ACE×10⁴ kt²	54.8	26.5	5th	108.5 (2015)

North Indian

May 2023 North Indian Tropical Cyclones

Name	Maximum CategoryMax Cat	Dates >39 mph	Maximum Sustained Winds	Minimum Central Pressure
Mocha	5	May 11May 11-14	160 mph	918 mb

North Indian Tropical Cyclone May Counts

Storm Type	Count	1991-2020 Mean	1981-2023 Rank*	1972-2023 Record
Tropical Storm Winds ≥ 39 mph (34 kts)	1	0.9 (9 in 10 Mays)	9th (tied with 19 other Mays)	3 (2010)
Cyclone Winds ≥ 74 mph (64 kts)	1	0.5 (5 in 10 Mays)	2nd (tied with 18 other Mays)	2 (2021)
Major Cyclone Winds ≥ 111 mph (96 kts)	1	0.3 (3 in 10 Mays)	1st (tied with 11 other Mays)	1 (12 Mays)
Accumulated Cyclone Energy ACE×10⁴ kt²	14.9	5.2	6th	20.0 (2020)

North Indian Tropical Cyclone Season Counts January-May 2023

Storm Type	Count	1991-2020 Mean	1981-2023 Rank*	1972-2023 Record
Tropical Storm Winds ≥ 39 mph (34 kts)	1	1.2	17th (tied with 17 other seasons)	3 (2010)
Cyclone Winds ≥ 74 mph (64 kts)	1	0.6 (6 in 10 seasons)	2nd (tied with 20 other seasons)	2 (2021)
Major Cyclone Winds ≥ 111 mph (96 kts)	1	0.3 (3 in 10 seasons)	1st (tied with 13 other seasons)	1 (14 seasons)
Accumulated Cyclone Energy ACE×10⁴ kt²	14.9	6.9	7th	22.2 (2019)

South Indian

May 2023 South Indian Tropical Cyclones

Name	Maximum CategoryMax Cat	Dates >39 mph	Maximum Sustained Winds	Minimum Central Pressure
Fabien	3	May 14May 14-21	115 mph	962 mb

South Indian Tropical Cyclone May Counts

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 Mays)	1st (tied with 12 other Mays)	1 (14 Mays)
Cyclone Winds ≥ 74 mph (64 kts)	1	0.1 (1 in 10 Mays)	1st (tied with 6 other Mays)	1 (7 Mays)
Major Cyclone Winds ≥ 111 mph (96 kts)	1	0.0 (0 in 10 Mays)	1st	1† (2023)
Accumulated Cyclone Energy ACE×10⁴ kt²	13.0	1.0	1st	13.0‡ (2023)
†Previous record 0 (67 Mays)
‡Previous record 8.2 (1993)

South Indian Tropical Cyclone Season Counts July 2022-May 2023

Storm Type	Count	1991-2020 Mean	1981-2023 Rank*	1956-2023 Record
Tropical Storm Winds ≥ 39 mph (34 kts)	9	10.3	30th (tied with 1 other season)	16 (1997)
Cyclone Winds ≥ 74 mph (64 kts)	7	6.0	11th (tied with 5 other seasons)	11 (2019)
Major Cyclone Winds ≥ 111 mph (96 kts)	4	3.5	7th (tied with 11 other seasons)	9 (2019)
Accumulated Cyclone Energy ACE×10⁴ kt²	132.9	94.2	7th	186.9 (1994)

Australia

No Australia Tropical Cyclones occurred during May 2023.

Australia Tropical Cyclone May Counts

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 Mays)	16th (tied with 27 other Mays)	4 (1963)
Tropical Cyclone Winds ≥ 74 mph (64 kts)	0	0.1 (1 in 10 Mays)	4th (tied with 39 other Mays)	2 (1986)
Major Tropical Cyclone Winds ≥ 111 mph (96 kts)	0	0.0 (0 in 10 Mays)	2nd (tied with 41 other Mays)	1 (1997)
Accumulated Cyclone Energy ACE×10⁴ kt²	0.0	0.8 (8 in 10 Mays)	16th (tied with 27 other Mays)	12.5 (1986)

Australia Tropical Cyclone Season Counts July 2022-May 2023

Storm Type	Count	1991-2020 Mean	1981-2023 Rank*	1956-2023 Record
Tropical Storm Winds ≥ 39 mph (34 kts)	9	10.6	28th	19 (1999)
Tropical Cyclone Winds ≥ 74 mph (64 kts)	5	4.8	14th (tied with 7 other seasons)	9 (1992, 1996)
Major Tropical Cyclone Winds ≥ 111 mph (96 kts)	4	2.4	5th (tied with 4 other seasons)	6 (2015)
Accumulated Cyclone Energy ACE×10⁴ kt²	66.5	59.5	12th	111.3 (1999)

Southwest Pacific

No Southwest Pacific Tropical Cyclones occurred during May 2023.

Southwest Pacific Tropical Cyclone May Counts

Storm Type	Count	1991-2020 Mean	1981-2023 Rank*	1956-2023 Record
Tropical Storm Winds ≥ 39 mph (34 kts)	0	0.2 (2 in 10 Mays)	9th (tied with 34 other Mays)	2 (1989, 1997, 2017)
Tropical Cyclone Winds ≥ 74 mph (64 kts)	0	0.1 (1 in 10 Mays)	4th (tied with 39 other Mays)	2 (2017)
Major Tropical Cyclone Winds ≥ 111 mph (96 kts)	0	0.0 (0 in 10 Mays)	2nd (tied with 41 other Mays)	1 (2017)
Accumulated Cyclone Energy ACE×10⁴ kt²	0.0	1.1	9th (tied with 34 other Mays)	28.6 (2017)

Southwest Pacific Tropical Cyclone Season Counts July 2022-May 2023

Storm Type	Count	1991-2020 Mean	1981-2023 Rank*	1956-2023 Record
Tropical Storm Winds ≥ 39 mph (34 kts)	6	6.9	17th (tied with 10 other seasons)	16 (1998)
Tropical Cyclone Winds ≥ 74 mph (64 kts)	3	3.7	19th (tied with 9 other seasons)	10 (1998)
Major Tropical Cyclone Winds ≥ 111 mph (96 kts)	1	1.9	19th (tied with 15 other seasons)	6 (2003)
Accumulated Cyclone Energy ACE×10⁴ kt²	25.3	49.8	28th	128.8 (1998)

Global

May 2023 Global Tropical Cyclones

Name	Maximum CategoryMax Cat	Dates >39 mph	Maximum Sustained Winds	Minimum Central Pressure
Mocha	5	May 11May 11-14	160 mph	918 mb
Fabien	3	May 14May 14-21	115 mph	962 mb
Mawar	5	May 20-June 3May 20-Jun 3	185 mph	897 mb

Global Tropical Cyclone May Counts

Storm Type	Count	1991-2020 Mean	1981-2023 Rank*	1972-2023 Record
Tropical Storm Winds ≥ 39 mph (34 kts)	3	3.8	23rd (tied with 8 other Mays)	7 (5 Mays)
Tropical Cyclone Winds ≥ 74 mph (64 kts)	3	1.8	5th (tied with 6 other Mays)	4 (1986, 1997, 2008, 2015)
Major Tropical Cyclone Winds ≥ 111 mph (96 kts)	3	1.0	1st (tied with 2 other Mays)	3 (2008, 2015, 2023)
Accumulated Cyclone Energy ACE×10⁴ kt²	81.6	24.9	1st	81.6‖ (2023)
‖Previous record 71.2 (2015)

Global Tropical Cyclone Season Counts January-May 2023

Storm Type	Count	1991-2020 Mean	1981-2023 Rank*	1972-2023 Record
Tropical Storm Winds ≥ 39 mph (34 kts)	17	24.9	40th (tied with 2 other seasons)	35 (1986)
Tropical Cyclone Winds ≥ 74 mph (64 kts)	12	13.2	21st (tied with 9 other seasons)	19 (1994)
Major Tropical Cyclone Winds ≥ 111 mph (96 kts)	7	7.5	16th (tied with 4 other seasons)	13 (2015)
Accumulated Cyclone Energy ACE×10⁴ kt²	247.9	203.9	9th	325.5 (1994)

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 basins 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.