John Mueller and the Google webmaster account (probably also John Mueller) said that having the date in your URL is fine. In fact, many publishers do just that because having a unique ID in the URL use to be a requirement for Google News.

This was posted twice on Twitter, here are those tweets:

Yea, it seems John manages both these accounts.

Again, dates in URLs are not a bad thing. Google doesn’t really care if you have them or not.

Forum discussion at Twitter.