ditto - i moved close to 15 years wview data to weewx
if you have not customised the wview schema, a copy of the database can be used directly by weewx.
caveat: any badly formatted fields in wview archive (e.g. if you manually patched a string value onto a float field to fix a problem years ago) will need to be cleaned up - and weewx includes a tool for just that purpose
the change from typical wview 30 min archive interval to typical 5 min weewx interval is transparent to the weewx graphics tool - they work fine with mixed intervals
[in the wview world, the archive interval is immutable. not so in the weewx world]
you can twiddle the weewx graphs much *much* more easily in weewx
and adding custom code is also much *much* easier