On the public Web page, could there be a button or other method for the user to switch between Fahrenheit/Centigrade and Imerial/Metric?
Great idea. If you have any votes left you might vote for your own feature request.
or perhaps better, display the data in the preference of the viewer, not the preference of the person providing the data. The browser probably tells the server enough info to do so.
Absolutely. The data is obviously there, the conversion is just math. NOT having the ability to set the preference (per-field like in the app would be nice) is surprising, and almost insulting to the brand.