Myth: It is obvious by the way he said “Wind Blast” back in Loguetown that Dragon has a wind Devil Fruit. Or maybe, Dragon ate a Devil Fruit that allows him to manipulate the weather. Why do you think a lightning bolt saved Luffy from being killed by Buggy? And what about the rain, when Dragon arrives at Loguetown?
Fact: Dragon did not say “Wind blast” in the manga, it was added in the anime. The original manga does not give any indication that Dragon had any effect on the weather other than being around when the storm hit. We do not know his power, although it is always a possibility. The speculation was re-invigorated when a rather powerful and convenient wind blast created a path to the ocean and the Revolutionaries during the fire of Gray Terminal, with some fans speculating the two instances were foreshadowing, but again there is no proof that this is correct.