Foreca (http://www.foreca.com/) - a very accurate forecast gives, for the States it is generally even better than the BBC
Pogoda.by (http://pogoda.by/) - it would be better not to add
Data for these cities and sources began to be collected only a week ago, so the monthly schedules are incomplete for now, but the rating should already mean something. Cities while new will not be added - I will deal with the analysis of clouds, precipitation and wind.
Upd: Ratings for Minsk and Helsinki are now incorrect, as well as the forecast from Intellicast. I will reload the data in the evening, but for now you can use the rest of the forecasts.