Campers, please help me to figure out what's wrong with my Weather App

Hey everyone!

I’ve been working in this project for hours and I’m getting stuck. I’ve been reading many tutorials and guidelines from MDN, W3Schools, Jquery and from other fellow developers, but it seems that I’m lacking something. I recycled some code that I used in the random quote machine, changing some features to handle a JSON instead of a JSONP. There are no errors to display in Codepen as you can see here: A simple weather app,
But when I go to the debug view, as you can see here Debug view,
I open Chrome development tools and I’m getting this message again and again Error in event handler for (unknown): TypeError: Cannot read property 'checked' of null so I’m guessing I have a serious problem with the way I coded the whole thing. Maybe my functions or variables are badly constructed. I appreciate any suggestion or idea.