Sorry the update server crashed overnight and It's now back up.
Here's how to ensure you get the latest update which allows Temp in C/F.
Go into Sol Tiempo (If you running OS4+ you'll need to check for updates, do this by tapping the lower right hand button and clicking "App Settings")
Wait 10 seconds for the update to apply.
Now when you tap on the "i" for a weather display provider you should see "Temperature Unit" under URL for Clientraw.txt
If you find the temperature settings is not being remembered, restart Sol Tiempo (for OS4+ you double tap home to bring up the multi-tasking bar, then hold Sol-Tiempo until it wiggles, then tap "-")
The tap the SolTiempo icon again and it will restart.
Let me know any probs.
Cheers
Kevin