1. Idaho Statehood Day: May 15 marks the day in 1890 when Idaho officially became the 43rd state in the United States.

2. Wildfire Season Begins: May 15 is the start of wildfire season in Idaho. Due to the state's dry climate and abundance of forests, wildfires are a common occurrence during the summer months.

3. Teton Dam Disaster: On May 15, 1976, the Teton Dam in eastern Idaho failed, resulting in a massive flood that caused significant damage to farms, businesses, and homes in the area.

4. Celebration of Idaho's Agriculture: May 15 is celebrated as National Agriculture Day in Idaho, honoring the state's rich farming traditions and important role in providing food for the nation.

5. Birth of Inventor Philo Farnsworth: May 15 is the birthday of Philo Farnsworth, an Idaho native who is credited with inventing the electronic television. Born on this day in 1906, Farnsworth went on to become a pioneer in the field of electronics and made significant contributions to the development of television technology.