Rated 3 out of 5 stars

... But, the weather date from AccuWeather.com seems to be significantly NOT accurate (Temperature offset by up to 10 degrees!)

High customizable. You can modify the UI any way you like.
A well written Add-on, too bad it relays on AccuWeather.com

Try "Forecastfox l10n":
https://addons.mozilla.org/en-US/firefox/addon/2024

This review is for a previous version of the add-on (0.9.6).