As blind and visually impaired folks, we've always liked Weather Underground for its no-nonsense, real-time weather info. They've released a service called Full Screen Weather that mashes up Google Maps with weather data for nothing but maps and up-to-the-minute weather info.
Just point your browser to http://www.fullscreenweather.com, enter your ZIP code, and get browsing. By default the map displays temperatures as measured from stations across Weather Underground's extensive reporting areas, but you can also switch to Precipitation and Cloud views (you can even play back cloud or precipitation movement over time). In the bottom-left of the window you get an overview of current conditions and a four-day forecast, with links to more extensive forecasts on Weather Underground proper.
For folks with low vision, the site is clean, simple, lightweight, and ad-free, which is to say, pretty great.
Click this link to visit http://www.fullscreenweather.com.