January 1, the 3rd Monday in January (which shall be the day of celebration for January 15), the 3rd Monday in February (which shall be the day of celebration for February 12 and 22), the last Monday in May (which shall be the day of celebration for May 30), June 19, which shall be the day of observation for Juneteenth Day, July 4, the 1st Monday in September which shall be known as Labor day, the 2nd Monday in October, November 11, the 4th Thursday in November (which shall be the day of celebration for Thanksgiving), December 25, the day of holding the partisan primary election, and the day of holding the general election in November are legal holidays. On Good Friday the period from 11 a.m. to 3 p.m. shall uniformly be observed for the purpose of worship. In every 1st class city the day of holding any municipal election is a legal holiday, and in every such city the afternoon of each day upon which a primary election is held for the nomination of candidates for city offices is a half holiday and in counties having a population of 750,000 or more the county board may by ordinance provide that all county employees shall have a half holiday on the day of such primary election and a holiday on the day of such municipal election, and that employees whose duties require that they work on such days be given equivalent time off on other days. Whenever any legal holiday falls on Sunday, the succeeding Monday shall be the legal holiday.