sWeather

S-weather is a great little tray application that can show the current temperature and weather conditions in your system tray, just like the Linux tray weather application, only in Windows, I reccomend it especially for XP since it doesn't have a built-in widget for this. Unlike other tray weather applications I've tried for Windows, this JUST WORKS, no messing around with it or restarting it all the time to refresh it, maybe it's because it uses Yahoo as the weather source, rather than a weather service. It has many features that are lacking in other applications like it, without the bloat contained in others. You can change the look of the icons, as well. On hover it gives more information, such as the day's projected high and low, and with one click you can get even more information in a small pop-up window. From there it's just one more click to open Yahoo weather for your chosen city in your default browser with even more information. You can also add more cities if you want to keep track of conditions in multiple cities. It's also ad-free.

[Edited by fixitmanarizona, March 26]