If each of the months has the same internal structure, do something like this:
<xsl:variable name="months" select="month">
<xsl:for-each select="$months[1]/*">
<xsl:variable name="p" select="position()"/>
<tr>
<td><xsl:value-of select="name()"/></td>
<xsl:for-each select="$months">
<td><xsl:value-of select="*[$p]"/></td>
Michael Kay
http://www.saxonica.com/
Author, XSLT Programmer's Reference and XPath 2.0 Programmer's Reference