Let's say you open a window. There is difference in temperature and relative humidity between inside and outside air. Which room quantity will equalize faster with the outside - temperature or humidity?
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Humidity will equalize mainly by convection (and somewhat with diffusion) whereas temperature, along with convection, will also use conduction and radiation. So my guess is temperature will equalize faster.
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2$\begingroup$ The thermal diffusivity of air is 19 mm^2/sec, while the molecular diffusivity of water vapor in air is 0.0016 mm^2/sec. $\endgroup$ Commented Dec 8, 2020 at 12:48
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$\begingroup$ @ChetMiller you should expand on that and post as an answer. The relative diffusivity (probably slightlly temperature - dependent) of H2O vapor is the important feature here. $\endgroup$ Commented Dec 8, 2020 at 14:04