Your old data will be meaningless in a new location. For example, a plot of this year's temperature will have an abrupt discontinuity. Better to retire your old data and start afresh.
All you have to do is move the old database and generated files aside. Plus, of course, modify weewx.conf for your new location. For example, if you did a package install it would look something like this:
sudo mv /var/lib/weewx/weewx.sdb /var/lib/weewx/weewx-nanaimo.sdb
sudo mv /var/www/html/weewx /var/www/html/weewx-nanaimo
If you did a setup.py install, like this:
mv /home/weewx/archive/weewx.sdb /home/weewx/archive/weewx-nanaimo.sdb
mv /home/weewx/public_html /home/weewx/public_html-nanaimo
-tk