I check the Band Conditions feature all the time. However, I’ve noticed more than once that the declaration of GOOD band conditions for 20m (I only use 20m) doesn’t always reflect the actual band conditions. For example, this morning 20m was shown as GOOD, while in fact the noise floor is high and I can hear very few operators. What gives?
My guess is that they’re predictions based on solar activity. To know how good/bad conditions are you just need to get on the air and try them! 