The app shall we say...is a somewhat acceptable, and I dare say, yet a reliable app? It is seriously in question. IMO? A wholeheartedly BEWARE what you see as a "SAFE TO FLY" recommendation! While the efforts of the designer(s) of the app may have tried to be so-called accurate in the offering advice as to weather conditions .You may find that their advice to be horrendously detrimental to your actual flight in conditions for your area. Following your local weather reports for real time actual weather reports for wind and other adverse weather conditions in your area are your best options.