Average Annual and Monthly Numbers of Tornadoes by State - Maps

U.S. Tornado Climatology

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General

Tornadoes can occur anyplace, but they are more likely in some locations than others. Check maps that show the average number of tornadoes in each of the United States over a year or by month, based on tornado observations from 1991-2010.

Where do these data come from?

Official counts of tornadoes come from NOAA's National Severe Storms Laboratory. Storm spotters have been trained to recognize tornado conditions and report what they see to the National Weather Service. Storm spotters can be emergency managers or even local people with a keen interest in severe weather who have taken formal storm spotter training in their community. Additionally, computer programs, called algorithms, analyze Doppler radar data and display it in ways that make it easier for forecasters to identify dangerous weather. A storm with a tornado observed by radar has certain distinguishing features and forecasters are trained to recognize them.

Additional information on tornadoes:

  • Recent Tornado Reports and Information
    A summary of recent tornadic activity in the contiguous United States, including monthly tornado counts and descriptions of significant events.
  • Historical Records and Trends
    Historical records and trends for tornadoes, including graphs and maps showing timing and occurrences over approximately 60 years.
  • Tornado Alley
    In the United States, there are two regions with a disproportionately high frequency of tornadoes.
  • Deadliest Tornadoes
    Most tornadoes do not result in death. As a result of improved forecasting and early warning systems, the death toll has dropped.