Google just announced on its blog that it will be adding a weather layer to Google Maps.
To add the weather layer, hover over the widget in the upper right corner of Google Maps and select the weather layer from the list of options. When zoomed out, you’ll see a map with current weather conditions from weather.com for various locations, with icons to denote sun, clouds, rain and so on. You can also see cloud coverage, thanks to our partners at the U.S. Naval Research Lab. And, if you look closely, you can also tell if it’s day or night around the world by sun and moon icons.