Typhoon2000.com - Tropical Cyclone Sizes

::.. How big is a midget/small/medium/large-sized system?

Tropical Cyclones are measured radially outward from the center to the outermost closed isobar or to the
lowest maximum sustained winds (1 or 10-min ave) of 55 km/hr or 30 knots. This distance, in degrees
(1 degree is approximately 110 km or 60 nm), determines the system's radius size (see table below):

Distance in
degrees
(°)
Distance in
kilometers
(km)*
Distance in
nautical miles
(nm)*
Size / Type
Examples
< 2
< 220
< 120
Very Small / Midget
TY Roke (Auring/2005)
2 - 3
220 - 335
120 - 180
Small
TY Muifa (Unding/2004)
3 - 6
335 - 665
180 - 360
Medium / Average
STY Betty (Herming/1987)
6 - 8
665 - 890
360 - 480
Large
STY Angela (Rosing/1995)
> 8
> 890
> 480
Very Large
STY Nanmadol (Yoyong/2005)

Source: JTWC's FAQ with additional conversion and examples by Typhoon2000.com

*Size of Tropical Cyclone is measured in radius.

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