I'm the keyboardist of a big band. And it happened a few times to me when we were playing outdoors:
The day got hot, a little rain brought refreshment and high humidity; or in the evening, when it gets colder and you start to play into the night - some moisture gets on my keys. At home or at rehearsals, I'm used to play with dry hands on dry keys so the fingers will easily move around; but this is not the case when moisture gets into play. The keys don't exactly become sticky, but they do become dull and difficult to play. According to my experience.
I got told that some piano players even like that feeling; I really don't. And I'm quite convinced that my playing then sounds bumpy and inorganic. No more groove at all.
I'm not intending to install a fan every time for just in case it may happen again. But have any of you experienced this, don't like it as much as I do and found some practical remedy?