Weather app showing wrong day and temperature

When I check the weather in the notification tray and in the built-in weather app it says it's Sunday and the temperature is 45 degrees where I am. That's incorrect. It's Thursday and 67 degrees. I also tried weather for major cities and it's showing the wrong day and temperature for them as well. I checked Yahoo Weather and that data is correct.

I restarted my phone and at some point it showed the wrong data for my town in the local weather page, but the correct weather when I manually added my town, but when refreshing it's wrong for both.

There's a number of complaints on Twitter about this. What's going on? How can Yahoo's weather be correct, but the iPhone's wrong since the iPhone weather app uses data from Yahoo?