display custom date with custom date format with datetime package

Question

using 'datetime' package, one can produce a custom date with custom date format like this:

\usepackage{datetime}
\newdateformat{nwfmt}{\the\day, \THEDAY \monthday, \THEYEAR}
\newdate{mydate}{21}{12}{2020}
\begin{document}
\nwfmt
\mydate
\end{document}

but this does not give what i want. I want something like this: "monday, 21 december, 2020", i.e. full name of day and month and no uppercase.

Answer 1

The \DayName from scrdate could be easily converted to lowercase, but the \monthname had to be explicitly defined (anglicizing Werner's answer). That's the best solution I could get for a complete lower-case date, looking like:

\documentclass[border=2pt]{standalone}
\usepackage{datetime, scrdate}
\newdateformat{nwfmt}{\MakeLowercase{\DayName{\THEYEAR}{\THEMONTH}{\THEDAY}},
                      \THEDAY\ \monthname[\THEMONTH], \THEYEAR}
\makeatletter
\renewcommand{\monthname}[1][\month]{%
  @orgargctr=#1\relax
  \ifcase@orgargctr
    \PackageError{datetime}{Invalid Month number \the@orgargctr}{%
      Month numbers should go from 1 to 12}%
    \or january%
    \or february%
    \or march%
    \or april%
    \or may%
    \or june%
    \or july%
    \or august%
    \or september%
    \or october%
    \or november%
    \or december%
    \else \PackageError{datetime}{Invalid Month number \the@orgargctr}{%
      Month numbers should go from 1 to 12}%
  \fi}
\makeatother
\newdate{mydate}{21}{12}{2020}
\begin{document}
\nwfmt\displaydate{mydate}
\end{document}