My previous post showed the weather for your specific location (it was currently hard coded in, but will be updated to use the Geolocation module). This was using the wunderground API to get these details based on your city and state (look at home.ts). In order to do this you will need to make an account on wunderground and generate a free (or paid) API key. Now you can edit src/providers/weather/weather.ts and insert your API key, which should get you up and running.
I ran into some issues while using wunderground, as it seems the website is very finicky. I was not able to request a key until I was asked to confirm my membership, and had to do so on mobile rather than their desktop site. While this may not be true for everyone, I wanted to give fair warning that it is not the most friendly API to set up, but very friendly, and easy to call. Just look through my GitHub repository (home.ts, home.html, home.scss, app.module.ts, and weather.ts)!