Figure 3. Diurnal distribution of tornadoes in the immediate Oklahoma City, Oklahoma area by CST hour, 1890-2008. Data based on initial tornado touchdown times, with hour HH defined as the period HH-30 to HH+29. Data from 12 am CST (1 am CDT) to 6 am CST (7 am CDT) are repeated in order to show the trend across the 12 am CST (midnight) (1 am CDT) period.