My wunderground sensors stopped working yesterday and it appears that the free api is being retired.
Thanks for the update. The service’s retirement was announced several months ago (I believe this post, in June, is one of the earliest ones here).
It appears to be a YMMV situation because my API key is still valid and I continue to receive weather data.
You are correct, sorry for the duplication. 
I did do a quick search on the forum but couldn’t see anything about it but just like my wife keeps telling me, I obviously didn’t look properly…
No worries. Knowing that your sensors stopped suggests the process of cancelling API keys is now underway.
I got an email from WU. Existing keys that are linked to a PWS will remain active until March 1. The new API should be open on Feb 15.
From that it sounds like the old API will stop on Feb 15.
wunderground pws users can get a new free api key
but…
the HA wunderground component will not work with it as there is a new API from ibm.
different api address, different exposure ( only a 5 day forecast and limited observations compared to the old api) etc, etc…
good to know thanks, but I’ve already moved on…
I’m now in a new weather relationship 