Dianmu: 2021 Western North Pacific

Dianmu reached 35 kt (65 km/h, 40 mph) (TS) in the 2021 Western North Pacific season, from 2021-09-21 to 2021-09-26, with track, wind and pressure and 0.3 ACE.

Data as of 2026-10-17. Last revised 17 October 2026 (2026-10-17).

Key Facts

Dianmu was a tropical storm at its peak in the 2021 Western North Pacific season.
Peak maximum sustained wind was 35 kt (65 km/h, 40 mph), reached on 23 September 2021, and the lowest pressure was 1,000 hPa.
The track runs from 21 September 2021 to 26 September 2021 with 41 six hourly positions.
Dianmu accumulated 0.3 ACE.
1 landfall is recorded, the first on 23 September 2021.

Track

21 September 2021 to 26 September 2021

Dianmu formed on 21 September 2021 and its track is coloured by category at each six hourly step, peaking as a tropical storm. Made with Natural Earth and IBTrACS. Ringed points mark landfalls or the latest advisory position.

Wind

Knots, six hourly

Maximum sustained wind in knots every six hours, from 15 kt (28 km/h, 17 mph) at the start to a peak of 35 kt (65 km/h, 40 mph).

Maximum sustained wind of Dianmu
Time (UTC)	Wind (kt)
2021-09-21T00:00:00Z	15 kt
2021-09-21T03:00:00Z	15 kt
2021-09-21T06:00:00Z	15 kt
2021-09-21T09:00:00Z	15 kt
2021-09-21T12:00:00Z	15 kt
2021-09-21T15:00:00Z	15 kt
2021-09-21T18:00:00Z	15 kt
2021-09-21T21:00:00Z	15 kt
2021-09-22T00:00:00Z	15 kt
2021-09-22T03:00:00Z	18 kt
2021-09-22T06:00:00Z	20 kt
2021-09-22T09:00:00Z	20 kt
2021-09-22T12:00:00Z	20 kt
2021-09-22T15:00:00Z	23 kt
2021-09-22T18:00:00Z	25 kt
2021-09-22T21:00:00Z	28 kt
2021-09-23T00:00:00Z	30 kt
2021-09-23T03:00:00Z	30 kt
2021-09-23T06:00:00Z	35 kt
2021-09-23T09:00:00Z	33 kt
2021-09-23T12:00:00Z	35 kt
2021-09-23T15:00:00Z	33 kt
2021-09-23T18:00:00Z	30 kt
2021-09-23T21:00:00Z	28 kt
2021-09-24T00:00:00Z	25 kt
2021-09-24T03:00:00Z	23 kt
2021-09-24T06:00:00Z	20 kt
2021-09-24T09:00:00Z	18 kt
2021-09-24T12:00:00Z	15 kt
2021-09-24T15:00:00Z	n/a
2021-09-24T18:00:00Z	n/a
2021-09-24T21:00:00Z	n/a
2021-09-25T00:00:00Z	n/a
2021-09-25T03:00:00Z	n/a
2021-09-25T06:00:00Z	n/a
2021-09-25T09:00:00Z	n/a
2021-09-25T12:00:00Z	n/a
2021-09-25T15:00:00Z	n/a
2021-09-25T18:00:00Z	n/a
2021-09-25T21:00:00Z	n/a
2021-09-26T00:00:00Z	n/a

Pressure

hPa, six hourly

Central pressure in hectopascals every six hours, falling to 1,000 hPa at the lowest.

Central pressure of Dianmu
Time (UTC)	Pressure (hPa)
2021-09-21T00:00:00Z	1008 hPa
2021-09-21T03:00:00Z	1008 hPa
2021-09-21T06:00:00Z	1008 hPa
2021-09-21T09:00:00Z	1008 hPa
2021-09-21T12:00:00Z	1007 hPa
2021-09-21T15:00:00Z	1008 hPa
2021-09-21T18:00:00Z	1008 hPa
2021-09-21T21:00:00Z	1008 hPa
2021-09-22T00:00:00Z	1006 hPa
2021-09-22T03:00:00Z	1008 hPa
2021-09-22T06:00:00Z	1006 hPa
2021-09-22T09:00:00Z	1008 hPa
2021-09-22T12:00:00Z	1004 hPa
2021-09-22T15:00:00Z	1006 hPa
2021-09-22T18:00:00Z	1002 hPa
2021-09-22T21:00:00Z	1004 hPa
2021-09-23T00:00:00Z	1002 hPa
2021-09-23T03:00:00Z	1003 hPa
2021-09-23T06:00:00Z	1000 hPa
2021-09-23T09:00:00Z	1002 hPa
2021-09-23T12:00:00Z	1000 hPa
2021-09-23T15:00:00Z	1004 hPa
2021-09-23T18:00:00Z	1004 hPa
2021-09-23T21:00:00Z	1007 hPa
2021-09-24T00:00:00Z	1004 hPa
2021-09-24T03:00:00Z	1007 hPa
2021-09-24T06:00:00Z	1004 hPa
2021-09-24T09:00:00Z	1008 hPa
2021-09-24T12:00:00Z	1004 hPa
2021-09-24T15:00:00Z	n/a
2021-09-24T18:00:00Z	1004 hPa
2021-09-24T21:00:00Z	n/a
2021-09-25T00:00:00Z	1004 hPa
2021-09-25T03:00:00Z	n/a
2021-09-25T06:00:00Z	1004 hPa
2021-09-25T09:00:00Z	n/a
2021-09-25T12:00:00Z	1002 hPa
2021-09-25T15:00:00Z	n/a
2021-09-25T18:00:00Z	1004 hPa
2021-09-25T21:00:00Z	n/a
2021-09-26T00:00:00Z	n/a

ACE Compared With the 2021 Season

Accumulated cyclone energy of named storms in 2021
Sam (North Atlantic)	54.0 ACE
Habana (South-West Indian)	34.2 ACE
Larry (North Atlantic)	31.9 ACE
Surigae (Western North Pacific)	28.7 ACE
Chanthu (Western North Pacific)	28.7 ACE
Linda (Eastern North Pacific)	25.4 ACE
Faraji (South-West Indian)	22.1 ACE
Mindulle (Western North Pacific)	21.9 ACE
Felicia (Eastern North Pacific)	21.4 ACE
Yasa (South Pacific)	19.8 ACE
Rai (Western North Pacific)	18.9 ACE
In-Fa (Western North Pacific)	14.9 ACE
Marian (South-West Indian)	14.2 ACE
Niran (South Pacific)	14.1 ACE
Ida (North Atlantic)	10.6 ACE
Elsa (North Atlantic)	9.9 ACE
Grace (North Atlantic)	8.6 ACE
Hilda (Eastern North Pacific)	8.3 ACE
Nyatoh (Western North Pacific)	8.0 ACE
Henri (North Atlantic)	7.8 ACE
Enrique (Eastern North Pacific)	7.7 ACE
Tauktae (North Indian)	7.7 ACE
Rick (Eastern North Pacific)	6.7 ACE
Malou (Western North Pacific)	6.6 ACE
Eloise (South-West Indian)	6.2 ACE
Seroja (South-West Indian)	6.1 ACE
Wanda (North Atlantic)	5.7 ACE
Conson (Western North Pacific)	5.4 ACE
Kompasu (Western North Pacific)	5.3 ACE
Champi (Western North Pacific)	5.0 ACE
Gulab:Shaheen-Gu (North Indian)	4.9 ACE
Namtheun (Western North Pacific)	4.8 ACE
Nora (Eastern North Pacific)	4.6 ACE
Ana (South Pacific)	4.4 ACE
Guambe (South-West Indian)	4.3 ACE
Pamela (Eastern North Pacific)	4.2 ACE
Odette (South-West Indian)	3.9 ACE
Olaf (Eastern North Pacific)	3.7 ACE
Chalane (South-West Indian)	3.7 ACE
Alicia (South-West Indian)	3.6 ACE
Yaas (North Indian)	3.6 ACE
Danilo (South-West Indian)	3.6 ACE
Cempaka (Western North Pacific)	3.4 ACE
Mirinae (Western North Pacific)	3.4 ACE
Bongoyo (South-West Indian)	3.4 ACE
Kevin (Eastern North Pacific)	3.2 ACE
Choi-Wan (Western North Pacific)	3.2 ACE
Jobo (South-West Indian)	3.2 ACE
Lucas (South Pacific)	3.2 ACE
Nida (Western North Pacific)	3.2 ACE
Lupit (Western North Pacific)	3.0 ACE
Omais (Eastern North Pacific)	2.9 ACE
Victor (North Atlantic)	2.5 ACE
Fred (North Atlantic)	2.4 ACE
Nicholas (North Atlantic)	2.4 ACE
Zazu (South Pacific)	2.2 ACE
Dujuan (Western North Pacific)	2.0 ACE
Joshua (South-West Indian)	1.9 ACE
Peter (North Atlantic)	1.8 ACE
Blanca (Eastern North Pacific)	1.7 ACE
Kimi (South Pacific)	1.6 ACE
Guillermo (Eastern North Pacific)	1.6 ACE
Rose (North Atlantic)	1.4 ACE
Dolores (Eastern North Pacific)	1.4 ACE
Carlos (Eastern North Pacific)	1.3 ACE
Lionrock (Western North Pacific)	1.2 ACE
Iman (South-West Indian)	1.1 ACE
Claudette (North Atlantic)	1.1 ACE
Julian (North Atlantic)	1.1 ACE
Bill (North Atlantic)	1.0 ACE
Ana (North Atlantic)	0.8 ACE
Bina (South Pacific)	0.8 ACE
Jawad (North Indian)	0.7 ACE
Marty (Eastern North Pacific)	0.7 ACE
Kate (North Atlantic)	0.7 ACE
Andres (Eastern North Pacific)	0.6 ACE
Jimena (Eastern North Pacific)	0.6 ACE
Sandra (Eastern North Pacific)	0.6 ACE
Teresa (North Atlantic)	0.6 ACE
Imogen (South Pacific)	0.5 ACE
Koguma (Western North Pacific)	0.5 ACE
Terry (Eastern North Pacific)	0.5 ACE
Mindy (North Atlantic)	0.5 ACE
Odette (North Atlantic)	0.4 ACE
Danny (North Atlantic)	0.4 ACE
Ignacio (Eastern North Pacific)	0.4 ACE
Dianmu (this storm)	0.3 ACE
Nepartak (Western North Pacific)	0.0 ACE

ACE is the sum of the squares of six hourly wind speeds, in units of 10,000 knots squared, counted while winds are at or above 34 knots.

Landfalls

Landfalls of Dianmu 2021
Date	Place	Position	Wind
2021-09-23	Open coast, place not named in the data	15.4, 108.7	33 kt (61 km/h, 38 mph)

Which Agency's Numbers

Wind and pressure from jtwc_wp,tokyo,us as carried in NOAA IBTrACS. Agencies average winds over different periods.

Related Headlines

Third party news, headline and link only

Download the Data

Sources: Source: International Best Track Archive for Climate Stewardship (IBTrACS) v04r01, NOAA National Centers for Environmental Information, doi:10.25921/82ty-9e16. Some agency values come from third parties such as JMA, IMD and BoM. (NOAA NCEI terms (citation requested)) Made with Natural Earth. Public domain map data. Borders are Natural Earth's de facto depiction. Data as of 2026-10-17. Storm records are best tracks and can be revised by the agencies.