Hey @JustinJohnson,
Thanks for sharing your project, it looks cool and managed to find the city I live in here in Sweden. Great work! 
A friendly reminder: code that executes on a user’s machine (like in the browser) can never truly be hidden. It can just be obfuscated to some degree. In this specific case, one doesn’t even need to look at the code to figure out the API key. Observing the network traffic to openweathermap.org is enough. Just something to keep in mind. 