i find accuweather.co.uk's hourly forecast is 90% of the time exactly spot on. i used to use weather.com and bbc weather too to get an average, but theyre full of crap. i know accuweather can get ti horribly wrong but for me its pretty good. best to check it last thing at night and then in the morning as it can change a lot!
I usually just pull the curtain back at about 6.30