<P> In the North Atlantic, a distinct hurricane season occurs from June 1 through November 30, sharply peaking from late August through October . The statistical peak of the North Atlantic hurricane season is September 10 . The Northeast Pacific has a broader period of activity, but in a similar time frame to the Atlantic . The Northwest Pacific sees tropical cyclones year - round, with a minimum in February and a peak in early September . In the North Indian basin, storms are most common from April to December, with peaks in May and November . </P> <P> In the Southern Hemisphere, tropical cyclone activity generally begins in early November and generally ends on April 30 . Southern Hemisphere activity peaks in mid-February to early March . Virtually all the Southern Hemisphere activity is seen from the southern African coast eastward, toward South America . Tropical cyclones are rare events across the south Atlantic Ocean and the far southeastern Pacific Ocean . </P> <Table> <Tr> <Th_colspan="6"> Season lengths and averages </Th> </Tr> <Tr> <Th> Basin </Th> <Th> Season start </Th> <Th> Season end </Th> <Th> Tropical cyclones </Th> <Th> Refs </Th> </Tr> <Tr> <Td> North Atlantic </Td> <Td> June 1 </Td> <Td> November 30 </Td> <Td> 12.1 </Td> <Td> </Td> </Tr> <Tr> <Td> Eastern Pacific </Td> <Td> May 15 </Td> <Td> November 30 </Td> <Td> 16.6 </Td> <Td> </Td> </Tr> <Tr> <Td> Western Pacific </Td> <Td> January 1 </Td> <Td> December 31 </Td> <Td> 26.0 </Td> <Td> </Td> </Tr> <Tr> <Td> North Indian </Td> <Td> January 1 </Td> <Td> December 31 </Td> <Td> 4.8 </Td> <Td> </Td> </Tr> <Tr> <Td> South - West Indian </Td> <Td> July 1 </Td> <Td> June 30 </Td> <Td> 9.3 </Td> <Td> </Td> </Tr> <Tr> <Td> Australian region </Td> <Td> November 1 </Td> <Td> April 30 </Td> <Td> 11.0 </Td> <Td> </Td> </Tr> <Tr> <Td> Southern Pacific </Td> <Td> November 1 </Td> <Td> April 30 </Td> <Td> 7.3 </Td> <Td> </Td> </Tr> <Tr> <Td_colspan="3"> Total: </Td> <Td> 87.1 </Td> </Tr> </Table> <Tr> <Th_colspan="6"> Season lengths and averages </Th> </Tr>

High humidity in the lower to middle levels of the troposphere