I completed this challenge last week and come across the same problem. After a few days of pulling my hair out I learned why. Since version 50 of Chrome, getting the user’s geolocation is blocked unless the site has a secure connection (URL has to be HTTPS not HTTP) and codepen I found is usually not secure. If is is the case, change the http to https and see if it works this time.
If this is the case, you will also have use a different weather api as well I’m afraid because the json object it sends you is through a http URL which Chrome blocks too. I used this api instead and it works really well https://www.apixu.com.
Hope this helps