Substitute workers fill in for regular employees. Hours may be four or eight per day depending on location. You must be able to work weekdays, weekends, evenings (until 8:00 PM) and before and after holidays. Substitute workers must have a reliable phone to receive messages and return phone calls. Library open hours cover Monday -Thursday 9:00 am to 8:00 pm; Friday and Saturday 9:00 am to 6:00 pm; Sunday 1:00 pm to 5:00 pm.