1. Oklahoma becomes a state - May 27, 1907 marks an important day in Oklahoma's history as it became the 46th state of the United States. The statehood celebrations were held in Guthrie, the former territorial capital of Oklahoma.

2. Tornado outbreak - May 27, 2019 was a deadly day as multiple tornadoes swept through parts of Oklahoma. The tornado outbreak resulted in at least three deaths and significant property damage.

3. The Oklahoma City bombing trial begins - On May 27, 1997, the trial of Timothy McVeigh began in Denver, Colorado for his role in the Oklahoma City bombing that took place on April 19, 1995. The bombing killed 168 people and injured hundreds more.

4. First intercollegiate football game in Oklahoma - On May 27, 1895, the University of Oklahoma and Kingfisher College played the first ever intercollegiate football game in Oklahoma. The University of Oklahoma won the game with a score of 34–0.

5. National Memorial Museum opens - On May 27, 2000, the National Memorial Museum in Oklahoma City opened its doors to the public. The museum honors the victims and survivors of the Oklahoma City bombing and educates visitors about the impact of domestic terrorism.