Typhoon Tip, the largest and most intense tropical cyclone ever recorded, reached a worldwide record-low sea-level pressure of 870 mbar (25.69 inHg) in the western Pacific Ocean.

Typhoon Tip, known in the Philippines as Super Typhoon Warling, was the largest and the most intense tropical cyclone ever recorded globally. The forty-third tropical depression, nineteenth tropical storm, twelfth typhoon, and third super typhoon of the 1979 Pacific typhoon season, Tip developed out of a disturbance within the monsoon trough on October 4 near Pohnpei in Micronesia. Initially, Tropical Storm Roger to the northwest hindered the development and motion of the system, although after the storm tracked farther north, Tip was able to intensify due to more favorable conditions within the region. After passing Guam, Tip rapidly intensified and reached peak sustained winds of 305 km/h (190 mph) and a worldwide record-low sea-level pressure of 870 hPa (25.69 inHg) on October 12. At its peak, Tip was the largest tropical cyclone on record, with a windfield diameter of 2,220 km (1,380 mi). The system slowly weakened as it continued west-northwestward and later turned to the northeast, in response to an approaching trough. After its approach, Tip made landfall in southern Japan on October 19, and became an extratropical cyclone shortly after its landfall. The system's extratropical remnants continued moving east-northeastward, until they dissipated near the Aleutian Islands on October 24.

A tropical cyclone is a rapidly rotating storm system with a low-pressure area, a closed low-level atmospheric circulation, strong winds, and a spiral arrangement of thunderstorms that produce heavy rain and squalls. Depending on its location and strength, a tropical cyclone is called a hurricane, typhoon, tropical storm, cyclonic storm, tropical depression, or simply cyclone. A hurricane is a strong tropical cyclone that occurs in the Atlantic Ocean or northeastern Pacific Ocean. A typhoon is the same thing which occurs in the northwestern Pacific Ocean. In the Indian Ocean and South Pacific, comparable storms are referred to as "tropical cyclones". In modern times, on average around 80 to 90 named tropical cyclones form each year around the world, over half of which develop hurricane-force winds of 65 kn or more.

Atmospheric pressure, also known as air pressure or barometric pressure, is the pressure within the atmosphere of Earth. The standard atmosphere is a unit of pressure defined as 101,325 Pa (1,013.25 hPa), which is equivalent to 1,013.25 millibars, 760 mm Hg, 29.9212 inches Hg, or 14.696 psi. The atm unit is roughly equivalent to the mean sea-level atmospheric pressure on Earth; that is, the Earth's atmospheric pressure at sea level is approximately 1 atm.