I was able to locate preferences for the app on my iPhone (icon under the Home iconas I recently learned). After that, I went to the bottom of the page (also not obvious). The setting was easy to modify; I just went from C to F, and after being prompted to check in, the new setting took effect immediately. I'm sure I'm missing something obvious, but if you're already logged in (on the app on your iPhone! ), the last step is to find Save by scrolling all the way down under Settings (in red, not grayed out). I did first access the site, but found that the temperature had been pre-set to Fahrenheit. I'm unsure if it was simply logging into the app (as app settings are ostensibly stored in the cloud) or saving app changes while signed into the app that performed the trick.