\documentclass[12pt,letterpaper]{amsart}
\usepackage[margin=5mm,footskip=5mm,paperwidth=217mm,paperheight=217mm]{geometry}
\usepackage{DejaVuSans}
\usepackage{array}
\renewcommand{\familydefault}{\sfdefault}
%\renewcommand{\arraystretch}{1}

\begin{document}

\setlength\parindent{0pt}
\setlength\extrarowheight{4pt}

\newcommand{\cw}{5mm}
\newcommand{\lb}{8mm}

\makeatletter
\newcommand{\thickhline}{%
    \noalign {\ifnum 0=`}\fi \hrule height 2pt
    \futurelet \reserved@a \@xhline
}
\newcolumntype{"}{@{\hskip\tabcolsep\vrule width 2pt\hskip\tabcolsep}}
\makeatother

\newenvironment{wcaltabw}[1][Month]
{\begin{tabular}{|>{\centering\arraybackslash}m{\cw}|>{\centering\arraybackslash}m{\cw}|>{\centering\arraybackslash}m{\cw}|>{\centering\arraybackslash}m{\cw}|>{\centering\arraybackslash}m{\cw}|>{\centering\arraybackslash}m{\cw}|>{\centering\arraybackslash}m{\cw}|>{\centering\arraybackslash}m{\cw}}
    \cline{1-7}
    \multicolumn{7}{|c|}{\bf #1}\\
    \cline{1-7}
    \it S & \it M & \it T & \it W & \it T & \it F & \it S \\
    \cline{1-7}
    \noalign{\vskip 1mm}
    \cline{1-7}
}
{\end{tabular}}

\newcommand{\patternOne}{
   1 &  2 &  3 &  4 &  5 &  6 &  7 \\
  \cline{1-7}
   8 &  9 & 10 & 11 & 12 & 13 & 14 \\
  \cline{1-7}
  15 & 16 & 17 & 18 & 19 & 20 & 21 \\
  \cline{1-7}
  22 & 23 & 24 & 25 & 26 & 27 & 28 \\
  \cline{1-7}
  29 & 30 & 31 &    &    &    &    \\
  \cline{1-7}
}

\newcommand{\patternTwo}{
     &    &    &  1 &  2 &  3 &  4 \\
  \cline{1-7}
   5 &  6 &  7 &  8 &  9 & 10 & 11 \\
  \cline{1-7}
  12 & 13 & 14 & 15 & 16 & 17 & 18 \\
  \cline{1-7}
  19 & 20 & 21 & 22 & 23 & 24 & 25 \\
  \cline{1-7}
  26 & 27 & 28 & 29 & 30 &    &    \\
  \cline{1-7}
}

\newcommand{\patternThree}{
     &    &    &    &    &  1 &  2 \\
  \cline{1-7}
   3 &  4 &  5 &  6 &  7 &  8 &  9 \\
  \cline{1-7}
  10 & 11 & 12 & 13 & 14 & 15 & 16 \\
  \cline{1-7}
  17 & 18 & 19 & 20 & 21 & 22 & 23 \\
  \cline{1-7}
  24 & 25 & 26 & 27 & 28 & 29 & 30 \\
  \cline{1-7}
}

\newcommand{\patternW}{
     &    &    &    &    &  1 &  2 \\
  \cline{1-7}
   3 &  4 &  5 &  6 &  7 &  8 &  9 \\
  \cline{1-7}
  10 & 11 & 12 & 13 & 14 & 15 & 16 \\
  \cline{1-7}
  17 & 18 & 19 & 20 & 21 & 22 & 23 \\
  \cline{1-8}
  24 & 25 & 26 & 27 & 28 & 29 & 30 &
  \multicolumn{1}{>{\centering\arraybackslash}m{\cw}|}{\bf W}\\
  \cline{1-8}
}

\begin{wcaltabw}[January]
  \patternOne
\end{wcaltabw}
\hspace{\cw}
\begin{wcaltabw}[February]
  \patternTwo
\end{wcaltabw}
\hspace{\cw}
\begin{wcaltabw}[March]
  \patternThree
\end{wcaltabw}

\vspace{\lb}

\begin{wcaltabw}[April]
  \patternOne
\end{wcaltabw}
\hspace{\cw}
\begin{wcaltabw}[May]
  \patternTwo
\end{wcaltabw}
\hspace{\cw}
\begin{wcaltabw}[June]
  \patternW
\end{wcaltabw}

\vspace{\lb}

\begin{wcaltabw}[July]
  \patternOne
\end{wcaltabw}
\hspace{\cw}
\begin{wcaltabw}[August]
  \patternTwo
\end{wcaltabw}
\hspace{\cw}
\begin{wcaltabw}[September]
  \patternThree
\end{wcaltabw}

\vspace{\lb}

\begin{wcaltabw}[October]
  \patternOne
\end{wcaltabw}
\hspace{\cw}
\begin{wcaltabw}[November]
  \patternTwo
\end{wcaltabw}
\hspace{\cw}
\begin{wcaltabw}[December]
  \patternW
\end{wcaltabw}

\thispagestyle{empty}

\end{document}