my recent research is showing that temperature and humididty do affect radio signals - trying to clarify that in this forum - not many opinions yet. if you google yr questions you will find that there are some technical pdf reports that say yes to yr question - i did not yet find any that say no.
Both are valid and possible. Supossing you are not affected by tail or front winds, solar interference can be checked on http://www.swpc.noaa.gov/, look for the estimated planetary k index. If 4 or above, expect possibility of erratic behaviour.Another factor could be temperature, i.e, air density, the colder air you fly, more air density and better sustentation.This means less rotations and lesser consumed energy/battery