Yagi passed over northern Hainan and directly over Haikou, before briefly making landfall over Xuwen County in mainland Guangdong Province and moving into the open waters of the Gulf of Tonkin.

The origins of Typhoon Yagi can be traced back to August 30, when the Japan Meteorological Agency (JMA) reported that a low-pressure area had formed approximately 540 km (330 mi) northwest of Palau.

[3] Deep convection activity became concentrated around a circulation centre, which was in a favourable environment with excellent equatorward and poleward outflow and warm sea surface temperatures of 29–30 °C (84–86 °F).

[7][8] Yagi then shifted northwestwards along the southwestern edge of a mid-level subtropical high,[8] which caused its convection to be sheared to the north and left the low-level circulation centre exposed.

[9] As the system progressed up the coast of Luzon island, the colder cloud tops in the CDO continued to expand,[10] and at 14:00 PHT (06:00 UTC) on September 2, the storm made landfall in Casiguran, Aurora.

[15] At around 06:00 UTC on September 3, the JMA reported that Yagi had intensified into a severe tropical storm due to warm sea surface temperatures and high ocean heat content.

[21][22] The JMA meanwhile upgraded Yagi to a violent typhoon, and estimated that it peaked in intensity with a minimum central pressure of 915 hPa (27.02 inHg),[23] and 10-minute maximum sustained winds of 195 km/h (120 mph).

[28] After making landfall over Hainan Province, the typhoon's structure continued to feature a 24 miles (39 km) diameter eye, a nearly complete eyewall, and spiral banding in the southern semicircle.

[29] Yagi passed over northern Hainan and directly over Haikou, before making another landfall in Xuwen County, in mainland Guangdong province and entering into the open waters of the Gulf of Tonkin.

[30][31] On September 7, Yagi, which had steadily reorganised and rapidly intensified again with a well-defined circulation centre and very strong convection—evidenced by a large band of cloud tops at −80 °C (−112 °F) or colder in the southern part of the system—made landfall over Haiphong and Quảng Ninh, Vietnam.

[36] Yagi continued to weaken rapidly as it moved southwestwards along the southeastern edge of a mid-level subtropical high after it made landfall,[37] becoming a tropical depression on September 8.

At their next bulletin, the agency also added Benguet; La Union; Nueva Ecija; Rizal; Laguna; Marinduque, some parts of Batangas; Bulacan; Pampanga; and Pangasinan, as well as Metro Manila to Signal No.

[47] Salvage operations for the MT Terranova, which sank in Manila Bay and caused an oil spill during Typhoon Gaemi (locally called Carina) in July, were also suspended.

[63] In response,[64] authorities advised against fishing in hazardous waters,[65] organising outdoor gatherings,[66] and recommended strengthening home defences and inspecting dykes, especially at landing sites.

Airports including Nội Bài (Hanoi), Cát Bi (Haiphong), Vân Đồn (Quảng Ninh), and Thọ Xuân (Thanh Hóa) were asked to temporarily suspend operations on September 7 during specific time periods.

The storm affected 7,622 homes, with 493 completely destroyed, caused power outages in 65 cities and municipalities, blocked roads in 175 locations, and rendered 31 bridges impassable.

[106] On September 4, the small asteroid 2024 RW1, provisionally known as CAQTDL2 and measuring about 1 m (3 ft 3 in) in size,[107] entered Earth's atmosphere over the Philippines;[108] it was discovered by Jacqueline Fazekas at the NASA-funded Catalina Sky Survey, though observing the resulting fireball from the ground was challenging due to Typhoon Yagi.

[86] Yagi also caused flooding in Yunnan Province, affecting 814 households and resulting in the relocation of 2,130 residents in Hekou Yao Autonomous County, located on the Red River on the border with Vietnam.

[62] Prior to Yagi's landfall on the country, severe weather related to the storm killed one person and uprooted trees in Ho Chi Minh City on September 4.

[88][89] According to a prior report by Vietnam, when Yagi made landfall in Haiphong and Quảng Ninh Province on September 7, maximum sustained wind speeds of 50 m/s (180 km/h) and peak gusts of 63 m/s (230 km/h) were observed at a weather station in Bãi Cháy.

[155] Widespread power outages occurred in Lào Cai, Cao Bằng, and Bắc Kạn provinces, affecting several hundred thousand residents.

[157] In Phú Thọ province, damage from the typhoon later resulted in the collapse of the Phong Châu Bridge [vi] on September 9, sending at least 10 cars and two scooters into the Red River.

[95] Philippine President Bongbong Marcos conducted aerial inspections of La Mesa Dam, Marikina, and Antipolo,[205] announcing that over ₱16 million (US$324,873.1) in humanitarian aid has been allocated to the hardest-hit areas.

[208] On the afternoon of September 10, the Presidium of the Vietnamese Fatherland Front Committee held a ceremony to launch a fundraising campaign to support people affected by the storm, when the state budget is still limited.

[220] The Japanese government, via the Japan International Cooperation Agency, has dispatched emergency supplies to assist Vietnam in recovering from recent storm damage, while South Korea donated US$2 million.

[223] The Singapore Armed Forces will deploy an Airbus A330 MRTT and two Lockheed C-130 aircraft to deliver humanitarian assistance to communities affected by Typhoon Yagi in Laos, Myanmar, and Vietnam.

[227] The embassy of Ireland in Hanoi announced on September 18 a €250,000 (US$277,000) contribution to support UNICEF in supplying clean water, sanitation, and hygiene resources to vulnerable children and families impacted by the typhoon.

[228] The Canadian embassy in Hanoi reported that Canada has committed C$560,000 (US$413,000) in humanitarian aid to help the Vietnamese people impacted by the heavy flooding and landslides resulting from Typhoon Yagi.

[229] The Ministry of Emergency Situations of Russia provided humanitarian aid, which was delivered to Lao Cai province of Vietnam, the area most severely affected by the typhoon.

[231] Most countries that provided aid expressed their condolences to Vietnam,[232][233][234] including Argentina, Belgium, Belarus, Brunei, Bulgaria, Canada, Cuba, Czech Republic, Germany, Kazakhstan, Laos, Norway, New Zealand, Seychelles, Singapore, Slovenia, Spain, Thailand, United Kingdom, Uzbekistan, and Vatican.