It is important to understand what part of the year, and what time of the day, severe weather is most likely. Those should be the times when your severe weather awareness is highest, as it is when you are most likely to be adversely impacted. Bear in mind though that tornadoes and severe weather can occur at any time of the year, day or night.
The NWS Norman's "Storm Spotter Resource Center" has a comprehensive severe weather climatology page that includes useful links and interesting facts. You also may want to visit the following links:
In Oklahoma and North Texas, tornadoes can happen at any time of the year. While we think of tornado season as being from mid March through mid June, we can see storms in any month. Remember that storms don't have a calendar, and don't care what month it is. As long as the right conditions come together, tornadoes can happen in December or August as easily as they can in April. A tornado has been recorded in Oklahoma in every month of the year.
For example, on January 25, 1967, four tornadoes occurred in the state of Oklahoma. Three of those tornadoes were rated an F2 on the Fujita Scale. Almost exactly ten years earlier, four tornadoes occurred on January 21-22, 1957 in Eastern Oklahoma. Two were rated an F2 and one was rated an F4 on the Fujita Scale.
Most tornadoes occur between 3 pm and 9 pm. But we can also have tornadoes after dark, which adds to the danger, the need to be prepared, and the need to have a plan to be safe.