In spite of its simple concept, this free Firefox add-on proves to be a handy addition to Mozilla's browser. As you might guess from its name, ForecastFox gives you instant access to current and upcoming weather from directly within Firefox. As soon as you enter your zip code or city name, the program will automatically retrieve the current conditions and the forecast for the rest of the day. ForecastFox lets you dock its toolbar--containing either icons, text, or both--in several locations, including Firefox's menu bar and navigation bar. Mousing over an icon returns weather-related data, and you can enable or disable any of the program's features, including its nifty Radar feature (complete with satellite image). You can also customize icons, choose between Celsius or Fahrenheit, and create different location profiles for those long-distance commuters.
ForecastFox also lets you decide how many days in the future you want to see weather, though it lacks 10-day or two-week forecasts. Any Firefox user who keeps an eye on the weather will appreciate this extension's convenience factor as well as the fact that it's free.