Full website administrators can choose your community's units of measurement preference from the "Settings" section in the Admin Portal. This setting will be used wherever measurements are displayed throughout your community website, like the weather's temperature.
How-to
In the “Settings” section of the Admin Portal, click on the “Community information” tab from the list of categories.
On the next page, click select the “Formatting” tab.
Under the header "Units of measurement," click on the drop-down menu to select which option you'd like used on your community website.
Lastly, click "Save."