<P> Tropical cyclones have affected Florida in every month of the year but March . Nearly one - third of the cyclones affected the state in September, and nearly three - fourths of the storms affected the state between August and October, which coincides with the peak of the hurricane season . Portions of the coastline have the lowest return period, or the frequency at which a certain intensity or category of hurricane can be expected within 86 mi (139 km) of a given location, in the country . Monroe County was struck by 26 hurricanes since 1926, which is the greatest total for any county in the United States . </P> <P> El Niño has the following effects on Florida climate: above average rainfall in the spring . This is followed by wildfire threat when rain dries up . Northern Florida is more susceptible to severe weather; below normal temperatures, increased number of low pressure systems in the Gulf of Mexico during the winter, and "almost always" reduces the frequency of storms and hurricanes . </P> <P> La Niña has the following effects: often dry conditions prevail in late fall, winter and early spring, increased risk of wildfires in spring and summer months, the temperatures average slightly above normal, and the chance of hurricane activity increases substantially . </P> <P> Long term forecasts are made based on these effects . However, they are easily overridden, in winter, by the Arctic oscillation and North Atlantic oscillations, which can only be predicted about two weeks in advance . These can drop the temperature noticeably from seasonal norms . </P>

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