The 2006 Pacific typhoon season was a destructive and deadly season, although it was below-average in terms of activity with a total of 23 named storms, 15 typhoons, and six super typhoons. Compared to the previous season, more typhoons inflicted damage across several countries, particularly China and the Philippines, some of which made landfall at higher intensities. The ratio of intense typhoons to all typhoons is at 0.73, the highest since 1970. The season ran throughout 2006, though most tropical cyclones typically develop between May and November. The season's first named storm, Chanchu, developed on May 9, while the season's last named storm, Trami, dissipated on December 20.

China was hit by several storms, with Tropical Storm Bilis and Typhoon Saomai being the most notable. Bilis became the costliest and second-deadliest typhoon of the season, causing $4.4 billion (2006 USD) in damages and killing at least 800 people. Saomai became the most powerful typhoon to strike the country in 50 years, and was responsible for 456 deaths and $2.5 billion worth of damages. The Philippines got hit by a total of six typhoons – the highest since 1974 – the most significant being Typhoons Xangsane and Durian. Xangsane was the strongest to affect Manila in 11 years, while Durian became the deadliest typhoon of the season, causing at least 1,000 fatalities. Meanwhile, Japan also had its share of destructive typhoons; Typhoon Shanshan hit the country in mid-September, resulting in 11 deaths and damages amounting to $2.5 billion. This season also featured Typhoon Ioke, the strongest Central Pacific hurricane, which also entered the basin and hit Wake Island; damages were estimated to be at $88 million.

The scope of this article is limited to the Pacific Ocean to the north of the equator between 100°E and 180th meridian. Within the northwestern Pacific Ocean, there are two separate agencies that assign names to tropical cyclones which can often result in a cyclone having two names. The Japan Meteorological Agency (JMA) will name a tropical cyclone should it be judged to have 10-minute sustained wind speeds of at least anywhere in the basin, whilst the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) assigns names to tropical cyclones which move into or form as a tropical depression in their area of responsibility located between 135°E and 115°E and between 5°N–25°N regardless of whether or not a tropical cyclone has already been given a name by the JMA. Tropical depressions that are monitored by the United States' Joint Typhoon Warning Center (JTWC) are given a number with a "W" suffix.

Seasonal forecasts TSR forecastsDate Tropicalstorms TotalTyphoons IntenseTCs ACE Ref Average (1965–2005) 26.7 16.9 8.6 305 March 7, 2006 27.1 17.1 8.4 298 May 5, 2006 29.0 18.6 9.2 326 June 7, 2006 29.0 18.6 9.0 315 July 5, 2006 29.0 18.6 10.0 349 August 4, 2006 29.0 18.6 9.3 325 2006 season ForecastCenter Tropicalcyclones Tropicalstorms Typhoons Ref Actual activity: JMA 39 23 15 Actual activity: JTWC 28 23 15 Actual activity: PAGASA 20 16 10

During the year several national meteorological services and scientific agencies forecast how many tropical cyclones, tropical storms, and typhoons will form during a season and/or how many tropical cyclones will affect a particular country. These agencies included the Tropical Storm Risk (TSR) Consortium of University College London, PAGASA and Taiwan's Central Weather Bureau. Some of the forecasts took into consideration what happened in previous seasons and the La Niña conditions that were observed during the previous year.

On March 7, Tropical Storm Risk issued its first forecast for the season at an extended-range, forecasting a close to average season of 27 tropical storms, 17 typhoons and 8 intense typhoons. The ACE predicted was around 298. By May 5, Tropical Storm Risk issued their second forecast for the season, raising their numbers to 29 tropical storms, 19 typhoons and 9 intense typhoons, with an ACE of 326. This is due to the observed warming of sea-surface temperatures in the Niño 3.75 region and current patterns within the Central Pacific, indicating slightly higher activity. TSR released its third forecast for the season on June 7, predicting the same numbers with the same reason. Though on their fourth forecast during July 5, TSR stated that the 2006 season will be 15% above the 1965–2005 norm. Therefore, they raised the number of intense typhoons to 10, and their ACE to 349. The other reason behind this is due to the fact that there was an increase in tropical activity and much warmer SSTs over in the Niño 3.75 region than the previous forecast. On August 4, TSR released their final forecast. They reduced the number of intense typhoons to 9, and the ACE to 325. This was because it was reported that a slight decrease in tropical activity from the previous forecast and is due solely of a slight decrease in SSTs over in the same region.

Seasonal summary

The accumulated cyclone energy (ACE) index for the 2006 Pacific typhoon season as calculated by Colorado State University using data from the National Hurricane Center was 321.3 units. Broadly speaking, ACE is a measure of the power of a tropical or subtropical storm multiplied by the length of time it existed. It is only calculated for full advisories on specific tropical and subtropical systems reaching or exceeding wind speeds of .

The Pacific typhoon season runs throughout 2006 and has no official bounds, though most tropical cyclones from this basin generally develops from the months from May through to October. Despite the season turned out to be active, most tropical cyclones developed during the second half of the year, with only one typhoon, Chanchu developing during the month of May. Some minor systems also developed before May, with the first tropical system of the year, Agaton, developing to the east of Philippines on January 20, bringing minor damages as it crossed the country few days later.

Tropical cyclogenesis had become much favorable during late June with formations of Jelawat and Ewiniar. It was also during the same time when NOAA had stated that the weak 2006–07 El Niño had started. From mid July to early August, three "back-to-back" storms made landfall over in China, which were Bilis, Kaemi and Prapiroon. With all three combined, more than 900 people have been killed and damages were reported more than US$5 billion. Shortly thereafter, environments throughout most of the basin became favorable with less shear, more convection and warmer water, as three simultaneous storms, Maria, Saomai and Bopha, formed and affected three different landmasses such as Japan, China and Taiwan, respectively. Later in the same month, Hurricane Ioke had entered the basin from the Central Pacific as the strongest Central Pacific storm in recorded history, as a Category 5 powerful storm.

On September, an unnamed and unclassified tropical storm have been discovered by meteorologist Gary Padgett and Dr. Karl Hoarau. Later, Typhoon Xangsane affected Luzon, Philippines, causing major damages with more than 200 people dead. The country saw four storms making landfall, with three of them reaching Category 4 or 5 super typhoon status. Typhoon Cimaron made landfall over in northern Luzon as a Category 5 super typhoon with minimal damages. By November, Typhoon Chebi made landfall in the same area as Cimaron, though effects from the typhoon were much smaller than Cimaron. Although by late November, Typhoon Durian made landfall in Bicol region. Combined effects with ash from the Mayon Volcano had killed over 1,500 people and damages at least US$530 million. Durian also crossed the basin and into the North Indian Ocean basin, the first time since 2003. During early December, two systems formed. Typhoon Utor crossed Visayas with minimal damage; and Tropical Storm Trami, a very weak system that didn't affect any landmasses became the final tropical cyclone and dissipated on December 20.

Systems

Tropical Depression Agaton

On January 20, the JMA began monitoring a minor tropical depression located about east of Mindanao in the southern Philippines. As it traveled in an erratic northwestward direction, it slowly became better organized. On January 23, the JMA assessed the storm to have attained winds of 10-minute winds). Around the same time, PAGASA began issuing advisories on the system and gave it the local name Agaton. The depression weakened as it crossed over northern Samar Island and southern Luzon. Traveling towards the west, the system failed to strengthen and dissipated on January 27 while located over the South China Sea, about halfway between Vietnam and Borneo.

Tropical Depression 01W (Basyang)

On March 4, a tropical depression formed out of a wave close to the equator southeast of Palau. The JTWC upgraded it to Tropical Storm 01W at 3 p.m. UTC the same day. The JTWC downgraded it back to a depression on March 5 due to shear, and it never regained tropical storm strength before dissipating on March 7.

Typhoon Chanchu (Caloy)

On May 8, the JMA started to track a tropical depression about northeast of Palau, and later the JTWC followed suit giving the designation of 02W. By the next day, 02W had intensified into a tropical storm, with the JMA naming it Chanchu. The PAGASA had also declared that Chanchu had entered their area, giving the local name Caloy. Chanchu reached typhoon intensity and made its first landfall over in Samar on May 11, and several hours later, it struck Mindoro at Category 2 typhoon intensity. As Chanchu emerged to the South China Sea, and moved northward, the storm explosively intensified into a Category 4 typhoon and reached peak intensity with 10-minute sustained winds of on May 15. By May 17, Chanchu rapidly weakened, becoming a severe tropical storm as it made its landfall over in Shantou, Guandong. Both the JMA and the JTWC would issue its final advisories on May 18 as it became extratropical.

In the Philippines, the storm caused 41 deaths and a total of ₱117.6 million (US$2.15 million) in damage. Though Chanchu didn't made landfall over in Vietnam, several ships sunk and were lost. A total of 18 people, who are fishermen, were dead. Chanchu is also the most intense typhoon on Hong Kong Observatory's record to enter the South China Sea in May. Chanchu necessitated the Strong Wind Signal no. 3 in both Hong Kong and Macau. In Hong Kong, the Gale force signal 8 should have been hoisted for at least 10 hours as sustained gales were affecting the Eastern part of the territory, where the hourly mean wind reached 83 km/h, with gust reaching over 100 km/h in some areas. Overall damage in China was at ¥7 billion (US$872 million).

Tropical Storm Jelawat (Domeng)

On June 24, the JMA started to track a weak tropical depression located to the southeast of Samar, Visayas. After crossing the archipelago and emerging into the South China Sea on June 26, PAGASA named it Domeng while the JTWC had started issuing advisories with the designation of 03W. Moving northwestward, 03W had entered in an area of favorable environments and intensified into a tropical storm, with the naming of Jelawat on June 27. Jelawat made landfall over Southern China and fully dissipated inland on June 29.

The storm dropped heavy rainfall across southern China and Haikou recorded a rainfall of during the storm passage. A total of rain fell in 16 hours in Kampung Bundu, Malaysia. The rainfall killed seven people and left one missing. The flooding from Jelawat ruined 200 square kilometres of farmland and destroyed 190 houses.Shanghai Daily | 上海日报 – English Window to China News

Typhoon Ewiniar (Ester)