Im using a FR945 daily and an Edge 830 for the rides. If you use more than one service of Garmin, something strange will become obvious about weather:
The Edge weather widget seems to use the next airport with weather information. Living about 30 car minutes from two of them away, one north, one south of use, its often the case that this information is not accurate.
Today a ran with the FR945. Before, I checked and it said 2° C in the Garmin widget, an hour later it said 3°C in the same widget (after the run). In the activity, it says 6.1°C.
The Running Power data field from Garmin relies on weather information. Wich source does this use? A fourth?
How about consolidating that *** and use one source for all? In the best case, the system with the tightest coverage. Maybe WeatherUnderground.