The National Day of Reason is a secular celebration  for humanists, atheists, secularists, and freethinkers. The day is celebrated annually on the first Thursday in May, in response to the statutory observance of a National Day of Prayer in the United States, which many atheist and secular groups deem unconstitutional.
The National Day of Reason is an annual event for people who don't believe in God or religion. It takes place on the first Thursday in May as a response to the US government's National Day of Prayer, which some atheists and secularists consider unlawful.