If someone creates seasonal textures, SH3Cmdr can manage them appropriately.
All you'd need do is create SH3Cmdr\Date sub-folders for the first month of each season in each year, ie:
\Date\19400301\data\<spring textures>
\Date\19400601\data\<summer textures>
\Date\19400901\data\<autumn/fall textures>
\Date\19401201\data\<winter textures>
\Date\19410301\data\<spring textures>
\Date\19410601\data\<summer textures>
\Date\19410901\data\<autumn/fall textures>
\Date\19411201\data\<winter textures>
etc...