According to Cambridge Grammar, the most common way of writing dates is as follows:
20 January 1993
and not
20th January 1993
However, the "th" is still produced by biber+biblatex by default:
\documentclass[british]{article}
\usepackage{babel}
\usepackage[backend=biber]{biblatex}
\begin{filecontents}{\jobname.bib}
@book{mybook,
author = {Author},
date = {1993-01-20},
title = {Wonderful Tiny Fact (WTF)}
}
\end{filecontents}
\addbibresource{\jobname.bib}
\begin{document}
\cite{mybook}
\printbibliography
\end{document}
While I am not arguing for or against the full stop after "Jan", I am arguing that using "th" is AGAINST the most widespread style. In addition to the above Grammar link, see the editorial style of the university of Bath, which explicitly forbids it. My British English teacher also explicitly considers it wrong.
Of course, there might be a technical solution to omit "th" (see Date format in LaTeX for the main text).
How to omit the suffixes ("st", "nd", and "th") in dates in the bibliography?
Can the current default setting of printing "th" actually be classified as a bug?


Jan, Feb, Mar, Apr, Jul, Aug, Sept, Oct, Nov, Dec.* (I'd forgotten about the other external link byt he time I wrote that comment)
– Chris H Apr 24 '17 at 13:46