Clock / Weather widget does not display on the home screen
Go to the app drawer. At the top, you should see Apps and Widgets.
Click Widgets, and scroll through the pages. Look for the weather widget.
Once you find the widget, long-press on it and drag it to your home screen.


EDIT #1: Here's an example. In this case, I am using the Accuweather app. AND, I'm not using the default launcher, but you should find something similar.