hi sorry i forgot to put the link in lol
https://www.davisworthing.co.uk/new/wxwinddetail.php
The data / table in the html already contains those invalid characters.
Probably you copied that table form another page which was not in utf-8.
When you want to do that another time:
Use a decent program editor, new document, set the new document to the original character set (f.i. 8859-1 ).
Copy the data from the original location.
Paste into the new document,
change the character set to utf-8, and save.
or
Use your program editor to replace all strange characters in the current html to a minus sign if that is what is needed.
Attached that part of that table with the - characters.
Wim