While most browsers and operating systems have an inbuilt way of updating your time zone settings, Firefox does not have a default time setting that can be easily changed. For the business or leisure traveler, this can be annoying. Without the accurate timezone, several apps and features like iMessage on Mac or Cortana on Windows 10 might not work properly. However, there is a Firefox add-on that addresses this critical over-site by Mozilla’s developer team.
Install the Change Timezone add-on (linked here). Once installed, go to the addon’s tab by clicking Ctl+Shift+A. Then in the addons tab, select extensions in the left-side menu. Now find the “Change Timezone (Time Shift)” addon in the list, and select options. Once there, if you scroll to the bottom of the Change Timezone Options page, you can select your timezone from the drop down menu labeled “Timezone (Default is Etc/Greenwich).”