To a person living on a beach in the Caribbean or crossing the Atlantic on a sailing ship, it's not obvious whether a commotion in the sky is a hurricane or some other storm system. When did people realize that hurricanes are a unique type of storm?
Trade winds from a general easterly direction occur almost all of the time in the Caribbean and tropical Atlantic. A hurricane approaching from any direction except from the south would change the wind direction because winds spiral counterclockwise into the hurricane. For example, a hurricane approaching from the east would cause the wind direction to back to northerly, while one approaching from the west (very rare in the tropics before recurvature occurs) would cause the wind direction to veer to southerly. If a hurricane approached from a general southerly direction, the wind would remain generally easterly but would gradually increase in speed and gustiness. Hurricanes are often accompanied by anticlyclonic outflow at upper levels; this could be observed via the motion of cirrus clouds.