[fwaits]

Found a key in HKCU\Software\HTC\Manila called Home_WeatherClock_CheckTime that would seem to be what we're looking for, however the value is in pure HEX code and even translating them to Decimal I'm not seeing values that seems like something I would expect.

The HEX value is:

D9 07 0C 00 04 00 0A 00 13 00 2E 00 23 00 00 00

If anyone wants to see if they can figure it out go for it. It would be nice to decipher it and be able to set the interval to whatever the user wants.