Labor unions decided to celebrate Labor Day at the beginning of September primarily because the date was chosen to fall roughly halfway between the Fourth of July and Thanksgiving. This timing was considered optimal for good weather and to avoid conflicting with other holidays. The first Labor Day parade took place in New York City on September 5, 1882, organized by the Knights of Labor and the Central Labor Union (CLU). The idea to hold Labor Day on the first Monday of September was adopted by the Knights of Labor in 1884 and quickly spread nationwide. Another practical reason for choosing September was to avoid May 1st, International Workers' Day or May Day, which had strong socialist and sometimes violent associations from labor riots such as the Haymarket Affair in 1886. The U.S. government preferred a more neutral, conciliatory holiday that honored American workers without the political baggage of May Day. Labor Day eventually became a federal holiday in 1894, following widespread labor unrest, including the Pullman Strike. President Grover Cleveland signed the legislation making it official as a way to make a gesture to the labor movement and acknowledge workers' contributions in a more broadly acceptable way. Thus, the start of September was chosen as a strategic and symbolic date to celebrate labor and workers in the United States.