What is the size of the typical hurricane/tropical cyclone?

Approximately 170 km (100 miles) wide. The size of the storm is determined by a balance of atmospheric forces, the two major ones being the Coriolis acceleration due to the rotation of the earth, and the low pressure region at the center of the storm. In order for hurricanes and cyclones to form and grow in size, the winds aloft ("wind shear") must also be low.

Source: NOAA

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