I'm guessing its a hygrometer and not a hydrometer? It all depends on the reason you need readings. If you're getting condensation, put it where it occurs the most, if its because your snake sheds badly take readings from both ends, maybe move the water dish around and see what suits best etc
youre right eeji its a hygrometer I only use it so I can keep an eye on humidity.snakey sheds fine I just want things to be just right
Hi Yalovit,
I would not really worry about adding one to your set-up unless there are issues with humidity or shedding issues. Otherwise you might become concious of humidity, when there's no real problem there.
I think most people don't bother with hygrometers unless they are having shedding problems (and some not even then). Corns do very well at around 40%ish (give or take about 15%) and as this is a fairly common range for a house to be, they normally don't need much help with it unless they have problems shedding when a moist hide can do the world of good
their natural environment is similar to ours (but warmer) so you should be fine. If its just general monitoring for your own peace of mind then it doesn't really matter about placement so long as its not right over the water.