The WU graphs should continue to work after Feb 15th since they use the CSV download from the PWS page on WU, not the WU API.
They have said
We’d like to remind our PWS owners/contributors:Your past data will always be [b]available to you for viewing and download in a web browser on wunderground.com[/b], just as it always has. If you are in the small minority of people who use the WU API and a corresponding WU API key to obtain data in .json format, here's what's happening: We'll open a registration page for you to get a new API key to get your data in .json format You'll sign up and get a new API key for the new API Once the registration page is open, we'll keep the old API and your old API key active for 2 weeks to allow transition time to your new keyWe’ll announce in the forum when the registration page opens.