SWATPlot is a stand-alone tool that allows you to extract output data from SWAT runs. You can extract data from reach, sub-basin, hru, pond, and reservoir outputs, from the same or different runs of SWAT. You can also include observed data if you have it.
You can of course use SWATPlot with MWSWAT, but you can also use it on the output from other SWAT interfaces.
SWATPlot writes to a comma-separated-values file, so you can manipulate your data further, or import it into other tools, but by default it is immediately displayed in the companion tool ...
SWATGraph is designed to visualise the output from SWATPlot, displaying the data as histograms or line graphs.
The two tools are free and open source. They come in a single installer for Windows. Just download and execute it.
A tutorial on using the two tools is available from the documents page.
The source code is available from the MapWindow subversion code repository http://svn.mapwindow.org/svnroot/MapWindow4Plugins/SWATPlotGraph. This is best accessed by a tool like Tortoise.