Pretty nice, right? The 4×2 (top) one looks similar to the clock/weather widget on the LG Optimus 2X, meaning it's quite beautiful, and the 4×1 (middle) and 2×1 (bottom) ones aren't too shabby either, especially if you're low on home screen space. Too bad they don't work as well as they look on the HTC EVO.
The widget itself comes from the GO Dev Team (the folks behind the Go Launcher) and is called GO Weather. It's free in the Market so you won't be wasting any money if you want to try it; just don't get your hopes up that it'll always work like you want/expect it to.
The biggest problem is that it won't always let you set your location, giving you a network error message whether you're on WiFi, 3G, or 4G instead. Not being able to do this obviously renders the widget unusable. Other problems are that it also doesn't update consistently, the time is sometimes incorrect, the AM/PM doesn't always change when it should, and the highs and lows can be off by a degree or two.
GO Weather is good when it works, and I think it looks better than the Sense clock/weather widget, but reliability can be a deal-breaking issue. It's working for me right now but since that wasn't the case just a few hours ago, I'm not confident how long this stretch will last.
If you're feeling lucky and you want the widget on your HTC EVO, cross your finger and scan the QR code below.