Generate a plot with a second vertical axis. The HAXIS= option specifies the AXIS1 definition. The VAXIS= option specifies AXIS2 and AXIS3 definitions in the PLOT and PLOT2 statements. Axis labels and major tick mark values use the default color. The VMINOR= option specifies the number of minor tick marks for each axis.

proc gplot data= minntemp;
   plot c2*month / haxis=axis1 hminor=0
                   vaxis=axis2 vminor=1;
   plot2 f2*month / vaxis=axis3 vminor=1;
run;
quit;