How do you Cupertino off and my home on the Home Screen?

See “Add, delete, and rearrange locations…” here.

Check the weather on iPhone - Apple Support

In the Weather app, enter the location in the search box and view the weather display. In the upper right, select Add.

Once you have the locations you want added and possibly with Cupertino or other locations you don’t want, select the … in the upper right of the main display of Weather app, and select Edit List, and you can then re-order entries and can remove entries you don’t want.