在python的RE模块中，date的正则表达式不匹配

I'm currently writing a piece of code to extract data from a list of observation sites (an example is given below). I currently have a list of regular expressions to remove any lines which don't contain data I'm looking for. All of the regular expressions successfully indicate the lines on which metadata is contained except for the one searching for the date. When tested at regexr.com, the expression works just fine, but when running code, I am unable to remove the lines. What am I missing to remove the lines containing dates?I'm currently writing a piece of code to extrac