 Although it doesn't appear to be particularly mountainous, Helensburgh is surrounded by coastal suburbs located virtually at sea level, while Helensburgh itself, due to an odd quirk of geography, is not.So while you would expect Helensburgh's weather to be more similar to Sydney's or Wollongong's, given their relative closeness to the north and the south, the fact that Helensburgh is around 250 metres higher above sea level than either of them does have a noticeable effect on its climate and weather patterns.On the flip side, extreme weather conditions affecting Sydney or Wollongong generally aren't felt in Helensburgh.