Yes, it’s true. According to the Zombie Research Society, May is the official Zombie Awareness Month.
Many films important to the evolution of the modern Zombie are set in the month of May, from the original Night of the Living Dead, 1968, to the well received Dawn of The Dead remake of 2004.
Also, because Spring naturally brings with it a sense of renewal and hopefulness, May is the perfect month to emphasize continued vigilance in the face of the coming Zombie Pandemic.
You can prepare for the coming Zombie Pandemic here: Zombie Research Society