Today in Auckland sunshine most of the day. Had early morning rain before sunrise. Tonight there are still puddles of water on my desk where it had sunshine and wind all day. Proves the point that an open window will do nothing but make the house cold.
We put a dehumidifier in the bedroom (quiet Mitsubishi) just outside the en-suite. Works well (as Richms said).
Actually we keep all our windows closed all the time, also keeps the flies and mozzies and dust out. Starting to get stuffy now, time to get that heat pump installed and some forced ventilation.
I would really like for some form of ducted dehumidifier since the cheap plugin ones are noisy, need emptying or else a drain hose put in (not easy in some locations) and only do the one room unless I leave doors open (which I hate doing)