National Weather Service United States Department of Commerce

Back-to-Back Pacific Storms to Impact the West Coast; Heavy Snow in the Central Appalachians

Back-to-back powerful Pacific storm systems to impact the Pacific Northwest and northern California through the end of this week with heavy rain, flooding, strong winds, and higher elevation mountain snow. A strong, long-duration atmospheric river will accompany the Pacific storms, bringing excessive rainfall and flash flooding to southwest Oregon and northwest California through the week. Read More >

Note: The original news item was issued in June 2005, but was last edited in October 2015.

For the first time since official records began in 1950, no tornadoes were reported in the state of Oklahoma in the month of May 2005.

Prior to 2005, the record lowest number of reported tornadoes in May was two, in 1988.

Up until 2005, May was the only month of the year that always had at least one tornado. Every other month has two or more years with no tornadoes in the records.

The most tornadoes ever recorded in May occurred in 2010, when 91 tornadoes were reported. The previous high total for May occurred in 1999, when 90 tornadoes were documented.

May typically marks the peak of tornado season in Oklahoma. During the period from 1950 to 2013, an average of 22 tornadoes have been reported in the month of May. May typically brings about 39 percent of the year's annual average tornado total of 56.

Other years with low May totals include:
  • May 1988 - 2
  • May 2012 - 3
  • May 1958 - 4
  • May 1967 - 4
  • May 2006 - 4
  • May 2009 - 4
  • May 2014 - 4

The months of May in 1952, 1969, 1970, 1972, 1978, and 1987 each saw only five tornadoes.

An average of 39 tornadoes occur for the 5-month period from January through May.

The most tornadoes ever recorded during the January through May time frame occurred in 1999, when 116 tornadoes were tallied.

The lowest January-May totals include:

  • January-May 1988 - 7
  • January-May 2014 - 8
  • January-May 1958 - 10
  • January-May 1989 - 10