Shiraz, thanks for that info!
As a beginner I don't really bother with weather forecasts, I look outside and if I can see stars I'll setup the scope. However I did a lot of preparations for the transit of venus, including using a number of long range forecasts online and ended up just following BoM and 7Timer for and fortnight before the event. I found 7Timer during those 2 weeks had the more accurate forecast when compared to the weather on the day, particularly the evening before it was bang on (clear, some clouds) while the BoM was miles off (overcast and storms).
Also its hard to know what the data size is they use for predictions. I found, by changing my lat/long location, that the forecast for me was identical for over 50km around (I was trying to find a location I could get to where the chance of rain for the transit was less than from home). Then when it did change it changed dramatically. So some services seem to have an average forecast for a broad region if there are only a small number of weather stations. You might have to look at the forecasts from a service around your area and see for yourself how wide the area covers (if you're right near a boundary in the forecasts you might be better averaging the two).
I also contacted observatories leading up to the transit and asked if they had a particular weather service they relied on. They all used BoM but said its only as a rough guide. It's generally okay to use for the two days before and not reliable for longer than that. The best forecast is still wait until the observing time and pop your head outside and judge for yourself
Out of interest, has anybody ever found any home weather stations producing a more reliable forecast (or any that really cater nicely to astronomers?).