Tropical Cyclone Frequency


Tropical cyclone frequency refers to the number of tropical depression, tropical storms, and typhoons that enter or originate in the Philippine Area of Responsibility (PAR) in a given year.

Tropical cyclone is defined as a non-frontal low pressure system of synoptic scale developing over warm waters having organized convection and a maximum mean wind speed of 34 knots or greater extending more than half-way around near the centre and persisting for at least six hours.

Basic dataTropicial depression, tropical storm and typhoon
SourcePhilippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA)

Tropical depression is a weak low pressure disturbance with a definite surface circulation having maximum wind speed of up to 63 kilometers per hour (kph) or approximately less than 25 mile per hour (mph). It has one or more closed isobars and is most common in the equatorial regions or intertropical convergence and less frequent in the trades.

Tropical storm a moderate tropical cyclone with maximum wind speed of 64 to 118 kph (25 to 75 mph) and    with    closed    isobars.

Typhoon, an intense tropical cyclone with maximum wind speed exceeding 118 kph.

Frequency of collectionAs arises
Frequency of disseminationAs arises
Temporal disaggregation As arises
Spatial disaggregationNational